
















Common Brickwork 
Architectural T erra Cotta 


Prepared Under Supervision of 

WILLIAM S. LOWNDES, Ph. B. 

MEMBER, AMERICAN INSTITUTE OF ARCHITECTS 
DIRECTOR, SCHOOL OF ARCHITECTURE AND BUILDING CONSTRUCTION 
INTERNATIONAL CORRESPONDENCE SCHOOLS 


COMMON BRICKWORK 

By D. Knickerbacker Boyd. F.A.I.A. 




ARCHITECTURAL TERRA COTTA 

By Charles E. White, Jr. •— / S ^ L> 


246 

Published by 

INTERNATIONAL TEXTBOOK COMPANY 


SCRANTON, PA. 


THssoi 


Common Brickwork: Copyright, 1920, by International Textbook Company. 

Architectural Terra Cotta: Copyright, 1920, hy International Textbook Com¬ 
pany. 


Copyright in Great Britain 


All rights reserved 


Printed in U. S. A. 


GcV‘ 5.to 



International Textbook Press 
Scranton, Pa. 


98623 






CONTENTS 


Note.— This book is made up of separate parts, or sections, as indicated by 
their titles, and the page numbers of each usually begin with 1. In this list of 
contents the titles of the parts are given in the order in which they appear in 
the book, and under each title is a full synopsis of the subjects treated. 

COMMON BRICKWORK p ages 

Brick . 1_ 7 

Manufacture of Brick. 2- 3 

Hand-made bricks; Machine-made bricks; Drying and 
burning of brick. 

Classification of Brick. 4- 6 

Size, Weight, and Quality of Bricks. 7 

Brickwork . 8-70 

General Discussion. 8-11 

Strength of brickwork; Measurement of brickwork. 

Bricklaying . 12-24 

Tools and methods; Scaffolding. 

Brick Walls. 25-32 

Types of brick walls; Thickness of walls. 

Bond in Brickwork. 33-44 

Standard forms; Bonding face brick; Bonding hollow 
walls; Bonding walls at right angles; Joining new walls 
to old walls. 

Openings in Walls. 45-52 

Brick arches in general; Chases and flues. 

Backing Up. 53-54 

Efflorescence. 

Hangers, Anchors, etc. 55-59 

Chimneys and Fireplaces. 60-70 

ARCHITECTURAL TERRA COTTA 

Advantages, Uses, and Designs. 1-78 

Introduction . 1 

Advantages and Uses of Terra Cotta. 2-4 



















IV 


CONTENTS 


ARCHITECTURAL TERRA COTTA— (Continued) 

Pages 

Designs of Terra Cotta. 5-20 

Characteristics affecting design; Plane surfaces; Modeling 
terra cotta; Coloring terra cotta; Designing to resemble 
other materials; Stock design; Strength and weight of 


terra cotta. 

Architect’s Drawings. 21-23 

Manufacturer’s Drawings. 24-27 

Modeling. 28-29 

Molds . 30 

Manufacture of Terra Cotta. 30-38 

Materials; Finishes and colors; Fitting and jmmbering 
the blocks. 

Details of Construction. 39-66 

Shipping and Handling Terra Cotta. 67 

Setting the Terra Cotta... . 68-78 











COMMON BRICKWORK 


Serial 1843 - Edition 2 

\ 

BRICK 

1. Definition and Description.—Bricks may be defined 
as solid building units made of burned clay. They are com¬ 
paratively small in size, therefore easily handled, and being 
already burned are extensively used in buildings that are 
intended to be fire-resistive and in other forms of construction 
that are permanent in character. When referred to in the 
mass, or as a building material, they are called brick. 

Brick can be made cheaply and, when hard burned and laid 
i.n good mortar, is one of the most durable building materials in 
use. Common brick can be used to form solid, or even hollow, 
walls when desired, or can be used to back up a wall that is 
faced with a most costly material, such as face brick, terra 
cotta or stone. While common bricks are manufactured mainly 
with a view to service, they may be used for facing walls. In 
many localities the clays or shales used in making common 
brick produce, when burned, a variety of colors and textures 
resulting in the most pleasing effects as laid in the wall. These 
effects may'be obtained by using the bricks as they come from 
the kiln without selecting, or by selecting and grading the 
bricks. The possibilities of artistic treatment of wall surfaces 
are not even limited by the range of color or texture. With 
the use of any good hard brick a variation in color effect and 
texture of wall surface may be obtained by varying the char¬ 
acter of the bond and the size and color of the mortar joint. 
This use of certain kinds of common brick is also discussed 
and illustrated in the Section on Face and Ornamental Brick¬ 
work. 


COPYRIGHTED BY INTERNATIONAL TEXTBOOK COMPANY. ALL RIGHTS RESERVED 





o 


COMMON BRICKWORK 


MANUFACTURE OF BRICK 

2. Ingredients. —The principal material used in making 
brick is clay, where naturally suitable as it comes from the 
clay bank, or a combination of clay and sand, called silicate of 
alumina. Suitable basic materials of this nature are found 
throughout almost every state in this country. Brickyards 
abound in nearly every locality and in the making of brick and 
other clay products a practically inexhaustible material is 
drawn upon. This material, as found in nature, generally con¬ 
tains small quantities of other chemical substances such as iron, 
magnesia, lime, potash, etc. Each of these substances has a 
particular effect upon the color, hardness, and durability of the 
brick, and by the judicious use of these substances, either alone 
or in combination, certain characteristics in the finished brick 
can be obtained. Such combinations are often made by mixing 
together two or more clays containing different chemical 
substances. 


HAND-MADE BRICKS 

3. In the process of making clay bricks by hand, the clay is 
mixed with water and worked to a plastic state in a pug mill, 
and then the soft plastic clay is pressed into molds by hand. 
The molds are sometimes dipped into water, just before being 
filled with the clay, to prevent the mud from sticking to them 
when the mold is removed. Bricks molded in these wet forms 
are known as slop bricks and also as water-struck bricks. Sand 
is sometimes sprinkled into the molds to prevent the clay stick¬ 
ing, or to produce a sand-finished texture on the faces as laid, 
and the bricks from sanded molds are called sanded bricks. 
After the bricks are shaped in the mold, they are removed and 
laid in the sun, or in a drying house, for 3 or 4 days, after 
which they are stacked in kilns and burned. 

The hand method of making bricks and the sun method of 
drying, being very slow and laborious, have been almost 
entirely displaced by more economical and expeditious ones in 
which the work is done by machinery. 



COMMON BRICKWORK 


3 


MACHINE-MADE BRICKS 

4. Nearly all bricks are now made by machinery. Where 
they are made on a large scale, steam shovels frequently are 
used for excavating the clay, and conveyors carry the raw clay 
to the mill and also convey the molded bricks to the drying 
sheds and the kilns. 

Machine-made bricks are usually formed by one of three 
methods known as the soft-mud, the stiff-mud, and the dry- 
clay process. 

5. Soft-Mud Process.— In the soft-mud process, the 
clay is soaked in water until soft. It is then thoroughly mixed 
by machinery, and pressed into molds by a plunger. The 
bricks are then dried and burned. 

6. Stiff-Mud Process.— In the stiff-mud process, 
the clay is first thoroughly ground, and just enough water is 
added to make a stiff mud. After this mud is mixed in a pug 
mill, it is placed in a machine having a die the exact size of 
the brick required. The opening in this die is made the size of 
either the end or the side of a brick. The machine forces a 
continuous bar of clay through this die, and as it emerges it is 
automatically cut into bricks, which are then taken to the dry¬ 
ing yard. The bricks that are cut on the ends are called end cut. 
Those cut on the sides are known as side cut. The soft bricks 
are placed in rows in a yard covered by a rough shed, with 
open sides, where they are sun or air dried for a considerable 
length of time or are run on special trucks into drying houses 
and are dried in from 4 to 8 days by steam or waste heat from 
the kilns. When properly dried they are placed in the kiln 
and burned. 

7. Dry-Clay Process. —The process often employed in 
the best work is the dry-clay process. In this method of 
manufacturing brick, the clay is used just as it comes from the 
bank, and is apparently perfectly dry. It contains, however, 
about from 7 to 10 per cent, of moisture. The clay is filled 
loosely into molds of the same width and length as a brick, but 
deeper than the required thickness of the brick. A plunger 




4 


COMMON BRICKWORK 


that exactly fits the mold is then forced in under heavy pres¬ 
sure and compresses the clay to the size of the brick desired. 
The bricks are then removed to the kiln and fired. 

Molded bricks are made in the same way, the difference 
being that the mold is made to give the shape of the brick 
required. 

Whenever the term pressed brick is used, it should mean 
brick made by the dry process. There are many so-called 
dressed or face bricks, however, that are made by recom¬ 
pressing soft-mud bricks. 


DRYING AND BURNING OF 1 BRICK 

8. Bricks must be dried before being burned. Soft-mud 
bricks naturally require a longer time to dry than stiff-mud 
bricks. Having been properly dried, they are placed in kilns 
and burned. The types of kilns used are the up-draft, the 
down-draft, and the continuous kilns. The details of these 
kilns and their operation will not be described here. The 
important thing is that the bricks shall be well burned and sat¬ 
isfactory in shape and color. It might be said, however, that 
bricks burned in the modern forms of kilns are more uniform 
in color, shape, and hardness than those made in the old- 
fashioned kiln. 


CLASSIFICATION OF BRICK 

9. Common Brick. —The term common brick includes 
all brick made for structural purposes and produced without 
artificial scoring or marking of the exposed surface to give 
especial texture. 

The distinguishing line between common and face brick in 
modern practice seems to be the special mixing of ingredients 
and the artificial coloring and scoring or rough texture, or 
the repressing process of the smooth brick, and the fact that 
face brick are graded, handled, and packed with great care. 

Many face-brick plants and nearly all paving plants produce 
a proportion of common brick. Face brick culls are sold as 


commons. 




COMMON BRICKWORK 


5 


The terms applied to grades of common brick vary in differ¬ 
ent parts of the country. In some places the bricks, although 
not alike, are sold without selection or grading. In other places 
the kiln is graded as front brick and back brick, the front being 
hardest burned. In others there are hard and kiln run brick. 

In the overburned brick called clinkers, the clay fuses and 
causes irregular shapes and sizes. These bricks are usually 
extremely hard and very durable. Clinker bricks are in favor 
with many architects for ornamental purposes and should be 
laid with proper bond, size and kind of joint and color of the 
mortar. 

Common bricks burned in the old-style up-draft kilns are 
classified according to their position in the kiln, which affects 
the amount of heat to which they are subjected. In some 
localities three grades of brick are produced in these kilns, ' 
namely, arch or clinker brick; red, or well-burned, brick; and 
soft, or salmon, brick. In other localities four grades are pro¬ 
duced, namely: rough-hard (corresponding to arch brick), 
straight-hard, stretcher, and salmon. 

Arcli, or clinker, brick is the name applied to the bricks 
that have been nearest the fire and are consequently overburned. 

Red, well-burned, or straight-hard, brick constitutes 
the hardest and the largest part of the product of the kiln; 
stretcher brick being a selection of the most uniform of these. 

Salmon brick is the name applied to those that have been 
farthest from the fire and are consequently underburned and 
soft. In many localities these are used for interior, or unex¬ 
posed walls, and others not carrying heavy loads. 

In certain localities the clay is of such a composition that 
the best brick from the kiln is of a salmon color and such brick 
should not be confused with the salmon brick just described. 

The American Society for Testing Materials has adopted 
names for common brick as follows: vitrified brick, hard brick, 
medium brick, and soft brick. These grades conform in 
general to the classification just mentioned. 

10. Face Brick.— Face bricks are made of specially 
selected materials so that the brick shall be of certain desired 


6 


COMMON BRICKWORK 


colors, and with the faces scored or of a rough texture. These 
bricks are described in the Section Face and Ornamental 
Brickzvork. Common bricks are often made or selected for 
color, fire-flashed effects and shape, and used for facing .brick 
walls. 

11. Pressed Brick. —Pressed bricks are those that have 
been pressed in a machine, and are usually hard, smooth, and 
have sharp corners and true shapes. They are used as face 
brick. 

12. Firebrick. —Firebricks are made from fireclay and 
are used for lining furnaces, lime kilns, fireplaces, and chimneys 
in factories. They are usually somewhat larger than ordinary 
building bricks, and should be of homogeneous composition and 
texture, uniform in size, of a regular shape, easily cut, and not 
fusible. The best firebricks are hand-molded. 

13. Paving- Brick. —Paving bricks are usually made 
by the stiff-mud process, being repressed to give them a better 
shape, and are composed of about three parts of shale clay to 
one part of fireclay. They are burned at a high temperature 
to the point of vitrification, that is, to a heat at which they 
begin to fuse or melt. These bricks, have a high crushing 
strength and absorb very little moisture. They are used prin¬ 
cipally for paving driveways, and occasionally for paving flat 
roofs on fireproof buildings. 

11. Hollow Brick. —Hollow bricks are made of a stiff- 
mud mixture by machinery, as holes must be formed in the 
body of the brick. Hollow bricks are now being made more 
generally by manufacturers of terra-cotta tile, as the material 
and machinery used in manufacturing tile is better adapted to 
making hollow brick than is the machinery used in brick 
making. 

15. Sand, or Sand-Lime, Brick. —The composition of 
sand brick is usually 95 per cent, of sand and 5 per cent, of 
slaked lime. This mixture is forced into molds under a very 
high pressure, and the bricks are removed from the molds and 
heated with superheated steam. These bricks can be made in 


COMMON BRICKWORK 


7 


many colors by artificial means, and can thus be used to effect 
the most pronounced designs. Sand bricks are manufactured 
by many firms in the United States, some of which make a very 
good dense brick, while others make an inferior sandy article. 


SIZE, WEIGHT, AND QUALITY OF BRICKS 

16 . Size and Weight.— Heretofore there has been no 
universally accepted standard size for brick in the United States. 
However, in accordance with the unanimous action of a joint 
conference of representatives of architects, contractors, manu¬ 
facturers, distributors, and users of common and face brick, the 
United States Department of Commerce, through the Bureau of 
Standards, recommends that recognized approximate dimensions 
of bricks shall conform to the following: 

Common bricks, including sand-lime bricks, concrete bricks, 
cement bricks, and rough face bricks, shall have a length of 
8 inches, a width of 3| inches, and a thickness of 2\ inches. 

Smooth face brick shall have a length of 8 inches, a width 
of 3J inches, and a thickness of 2\ inches. 

While it is not compulsory for a brickmaker to conform to 
these sizes, a great majority have done so. Bricks taken from 
the same kiln will vary in size due to the varying amounts of heat 
to which they have been subjected. The weight of bricks varies 
with the material used in their manufacture, and with their 
size. Common bricks will average about 4\ pounds each. 

Fire brick and sewer brick are approximately the same size 
as common brick. Paving brick are somewhat larger, being 
from 8 to 9 inches in length, 3 to 3f inches in width, and 3f to 
4\ inches in thickness. 

IT. Quality. —All bricks should be of uniform dimen¬ 
sions, free from twists, cracks, and pebbles, and should have 
sharp corners. The bricks should be well burned but not 
vitrified lest they become brittle. When two bricks are struck 
together, they should emit a metallic ring. A good brick will 
not absorb over 10 per cent, of its weight of water if allowed 
fo soak for 24 hours. 




8 


COMMON BRICKWORK 


COLOR OP BRICK 

18. The color of brick is usually not considered of any 
importance in common brickwork, but as walls of this kind of 
brick are sometimes exposed to view, the selection of bricks as 
to color and shade may be desired and consequently the archi¬ 
tect’s specifications should clearly state if this selection is 
required. 

The color of common bricks depends largely upon the kind 
of clay used in making them and the temperature attained in 
the kiln during the burning. 

Bricks burned in down-draft kilns are more uniformly 
burned and are consequently of a more uniform red color. 


BRICKWORK 


GENERAL DISCUSSION 

19. Definition. —By the term brickwork is meant any 
construction made of bricks laid up in mortar. It can readily 
be seen that the strength of brickwork is not dependent on the 
strength of the brick alone. Other factors influence this, such 
as the strength of the mortar and the method of laying up and 
bonding the brick. Therefore, the value of brickwork, so far 
as strength and stability is concerned, may be decreased by the 
use of inferior mortar or by being laid by a bricklayer who does 
not understand his trade. 

20. Importance of Mortar. —In laying bricks, it is 
customary to bed them in mortar. The mortar serves several 
purposes. It tends to make the wall waterproof and air-proof 
under ordinary conditions; it forms a cushion to take up the 
irregularities in the bricks and thus distributes the pressure 
evenly, and it bonds the whole wall into one solid mass, which 
increases its strength and stability. 

Mortar for brickwork may be made of various combinations. 
It may be formed either of slaked or hydrated lime and sand in 




COMMON BRICKWORK 


9 


proper proportions, or of lime and sand mixed with a small 
quantity of cement. It may also be made of cement and sand, 
or cement and sand to which a small percentage of slaked or 
hydrated lime is added. Lime mortar is, however, to be 
avoided in work coming in contact with earth or subject to 
dampness. Mortars of various kinds and qualities are more 
fully discussed in the Section Limes, Cements, and Mortars. 

21. Size of Mortar Joints. —With soft-mud or stiff- 
mud bricks there are likely to be some irregularities which 
make necessary larger mortar joints than are generally 
required for pressed brick. For this reason common bricks 
are generally laid in mortar about ^ inch to ^ inch in thickness. 

If a wall is faced with common bricks or bricks that have a 
rough texture, the joints in the facing are sometimes made as 
much as J inch in thickness and the backing is adjusted either 
by additional courses of bricks or thicker mortar joints than 
usual to bring the two kinds of brickwork to the same level, so 
that they can be bonded together at approximately every six 
or eight courses in the height of the wall. 


STRENGTH OP BRICKWORK 

22. Bricks for ordinary requirements are seldom tested for 
crushing strength, as the masonry formed of well-burned brick 
laid in good cement mortar will carry all ordinary loads. 
Bricks should not fail, however, under a crushing load of less 
than 1,800 pounds per square inch. 

The strength of brickwork is influenced by the quality of the 
brick and the mortar of which it is composed. In cases where 
the brick is harder than the mortar, the latter is the factor that 
determines the strength of the brickwork. For this reason the 
load that may be placed upon brickwork varies with the kind of 
mortar that is used in its construction. These allowable loads 
are stated in the building laws in various localities. Local 
building laws should therefore be consulted when determining 
the loads on walls of buildings that come under the jurisdiction 
of such laws. Where no such laws exist, the Building Code 



10 


COMMON BRICKWORK 


recommended by the National Board of Fire Underwriters is 
authority for the statement that 111 pounds per square inch 
may be taken as a safe load for masonry formed of bricks 
laid in good lime mortar; 208 pounds per square inch for lime 
and Portland cement mortar; 208 pounds for natural cement 
mortar and 250 pounds for Portland cement mortar in the 
proportion of three parts of sand to one part of cement, of 
which not more than 15 per cent, of the Portland cement by 
volume may be replaced by an equal amount of dry hydrated 
lime. 


MEASUREMENT OP BRICKWORK 

23. The usual method of measuring brickwork is by the 
thousand bricks laid in the wall. A customary method of esti¬ 
mating the number of bricks in a piece of brickwork is first to 
determine the entire area of the face of the wall in square 
feet, measurements being taken on the outside of the wall, and 
not on the inside. This is done to offset the extra labor that is 
required in laying up the corners or angles. The number of 
bricks is computed approximately from these areas, using the 
number of bricks to the square foot as shown in Table I. Thus, 
when using a brick 8"X3f"X2|", laid with a £-inch joint, there 
would be 6.17, or 6J, bricks per square foot for a wall 4 or 
4J inches, or 1 brick, thick; 12^ bricks for a wall 8 or 9 inches, 
or 2 bricks, thick; 18J bricks for a wall 12 or 13 inches, or 

3 bricks, thick; 24f bricks for a wall 16 or 17 inches, or 

4 bricks, thick, and so on, 6J bricks per square foot being 
added for every additional brick in the thickness of the wall. 
The estimate is then based on the number of thousands of 
brick, at a suitable price per thousand, including labor and 
mortar. For example, a wall 24 feet long, 12 feet high and 
20 inches, or 5 bricks, thick, would contain 24X12 = 288 square 
feet 5 bricks thick. At 6J bricks this would be 288X5X6^ 
= 8,880 brick. 

24. The window and door openings in brick walls should 
always be deducted. While formerly it was in some places the 
custom not to deduct openings in estimating brickwork, modern 



COMMON BRICKWORK 


11 


methods adopted by all careful and efficient contractors include 
the figuring out with exactness the number of bricks required, 
as above indicated. This applies with force to the quantity of 
mortar necessitated for the brick. If walls are built hollow a 
deduction is likewise made for absence of brick and mortar 
therein. I he same is true of all flues in chimneys, the saving 
in brick alone paying for the cost of the flue lining which 

TABLE I 

NUMBER OF BRICKS TO THE SURFACE FOOT FOR 
DIFFERENT SIZES OF BRICKS WITH JOINTS 
OF VARIOUS THICKNESSES 


Size of Brick 
Inches 

1 

Thickness of Joint 

3 

1 6 

A 

4 

i 

5 

1G 

a 

8 

7 

1G 

1 

2 


Number 

of Bricks 


7JX3§X2§ 

7.31 

7.08 

6.86 

6.65 

6.45 

6.26 

7fX3fX 2J 

7.44 

7.20 

6.97 

6.75 

6.55 

6.35 

8 X3fX2i* 

7.22 

6.98 

6.76 

6.55 

6.35 

6.17 

8 X4 X2\ 

6.55 

6.35 

6.16 

5.98 

5.81 

5.65 

8JX3JX2J 

7.00 

6.78 

6.56 

6.36 

6.17 

5.98 

8^X4 X2i 

7.00 

6.78 

6.56 

6.36 

6.17 

5.98 

8iX4^X2f 

6.47 

6.27 

6.08 

5.90 

5.73 

5.57 

8iX4iX2i 

6.17 

5.99 

5.81 

5.64 

5.49 

5.33 

9 X4JX3 

4.92 

4.79 

4.67 

4.55 

4.45 

4.33 


^Standard size of common and rough face brick recommended by the 
Bureau of Standards of the Department of Commerce. 

should invaribly be used, except in the case of thick walls as 
mentioned in the articles on Chimneys and Fireplaces. 

25. In Table I is given the number of bricks required tor 
1 square foot of face of a wall one brick thick—that is, having 
a thickness equal to the width of a brick—when laid with mor¬ 
tar joints of different thicknesses and bricks of various sizes. 

26. This table will be found useful in estimating the num¬ 
ber of bricks in any wall. To find the number of bricks per 































12 


COMMON BRICKWORK 


square foot of face of a wall of any thickness, find in the table 
the number of bricks per square foot of face of wall for the 
size of brick and thickness of joint that are to be used and 
multiply this number by the number of bricks in thickness of 
the wall. The result will be the number of bricks per square 
foot of face of the wall in question. 

27. For example, according to the table, if bricks 8 in. 
X3j in.X2^ in. in size are to be used, with mortar joints f inch 
in thickness, the number of bricks per square foot of the face 
of the wall will be 6.55, if the wall is one brick in thickness; 
if the wall is two bricks in thickness, it will contain 13.10 
bricks; if three bricks thick, 19.65 bricks; if four bricks thick, 
26.20 bricks. 

It will be observed in Table I that the two 8i-inch bricks 
show the same number of bricks per surface foot. The reason 
for this is that the 8J- and 2i-inch dimensions are the only ones 
that show on the face of the wall. The 3f- and 4-inch 
dimensions afifect only the thickness of the wall. 

28. Labor Required. —The amount of labor required for 
laying brick is a very uncertain quantity. An average man may 
lay from 750 to 1,000 bricks per day where the work is some¬ 
what broken up and there are openings, or where the walls are 
thin. On thick straight walls with few openings a man may 
lay 1,200 to 1,500 bricks per day. 


BRICKLAYING 


TOOLS AXD 3IETHODS 

29. Tools Used in Bricklaying. —The tools that are 
required in building brickwork are a two-foot rule, a long and 
a short plumb-rule, a level, a large steel trowel, a small steel 
trowel, a cutting-out hammer, a bricklayer’s set, a brick jointer, 
wooden gauges for measuring bricks, a mason’s linen line, chalk, 
a pencil, and leather protectors for the hand when laying 
wet or rough-cut bricks. 




COMMON BRICKWORK 


13 


oO. The long' plumb-rule, or plumb, should be from 
o feet 6 inches to 4 feet long, about 3f inches wide, and about 



1J inches thick, with two plumb-glasses at opposite ends, like 
those shown at b in Fig. 1. 

The short plumb-rule, or plumb, should be from 16 in. 
to 18 in. long, with one plumb-glass like that shown at b in 
Fig. 1 and one level glass, as at a in Fig. 1. 

31. In Fig. 1 is shown what is known as a com¬ 
bination plumb-rule and level. It is used in a hori¬ 
zontal position as a level and the level glass a indicates 
when the level is exactly horizontal. It is used as a 
plumb-rule by holding one edge against the work to 
be plumbed and observing the level glasses b. A 
plumb-bob may be suspended from ekher end of the 
instrument so that it will hang in one of the open¬ 
ings d. The work is then tested by holding one edge 
of the plumb-rule against it and moving the instru¬ 
ment until the plumb-line coincides with the center 
line on the face of the plumb; then if the work does 
not coincide with the edge of the rule it is out of 
plumb or not perpendicular. 

32. A simple form of plumb-rule, shown in 
Fig. 2, is made of a piece of board a J inch thick and 
3 or 4 inches in width. The edges of the board and 
the line d are parallel. A plumb-bob b is suspended 
on a cord fastened through the notches at the top of 
the rule and hangs in the opening c. When the 
edge of the rule is placed against a vertical surface 
and the line coincides with the middle line d on the 
rule the surface is plumb. A plumb-rule of this description 
may be easily made and is very accurate but is not so con¬ 
venient as a rule with level glasses. 

246—2 



Fig. 2 







































































14 


COMMON BRICKWORK 


The advantage of the leveling glasses in the plumb-rule 
is that the wind does not interfere with its action. In the case 



of a plumb-bob suspended from a cord, even a small breeze 
causes motion of the bob, which interferes with its usefulness. 

33. The principal tool used by a brickmason is the trowel, 
the form and use of which is illustrated further on in Figs. 8, 9, 
10, and 11. These trowels are made from 9J inches to 



11 inches in length. Pointing trowels are made from 4 tc 
7 inches in length. 















COMMON BRICKWORK 


15 


34. A cutting-out liammer should weigh not less than 
3 j pounds and not more than 4 pounds, exclusive of the handle. 
There are many types of hammers that 
can be used for cutting out, but the one 
shown in Fig. 3 will enable a first-class 
man to do the most work with the least 
fatigue. In this figure is also shown the 
method of splitting a brick by means of 
the hammer. A line a b c is formed 
around the brick by means of light blows 
of the hammer and then a sharp blow is 
given which causes the brick to split at 
approximately this line. Any rough 
places on the split faces of the brick are 
trimmed off by the blade of the hammer, 
which is called the peen, or pecin, as 
shown in Fig. 4. 

35. A "brick set, shown in Fig. 5, 
is a chisel with a broad cutting edge. It 
is used when it is necessary to make a cut 
having straight edges, so that the cut 
portion may show on the face of the wall, or to make plumb 
joints with adjacent bricks. 

3G. A jointer, shown in Fig. 6, is a tool that is used to 
form a true, even, and smooth surface on the face of the mortar 
between the bricks. Except where common bricks are exposed 
for effect this -tool is not generally used, as the joints of mortar 




are struck with the trowel as the work progresses; but a brick- 
mason should possess one for use in connection with such face 








































1G 


COMMON BRICKWORK 


effects or face-brick work. Such a tool, at the very best, gets 
dull and loses its shape quickly, owing to the wearing action of 
the sand in the mortar,' consequently it should be made of the 
hardest tempered steel that is obtainable. At a, b, and c, 
Fig. 6, are shown sections through jointers of different kinds. 
The edges of these jointers are curved or pointed so as to 
give different profiles to the mortar. The ends d and e of the 
jointer may have different sections, so as to be useful for 
striking two shapes of joints. 

37. Wooden gauges, shown in Fig. 7 (a), are used to 
test the lengths of bricks when they are to be selected of a uni¬ 
form size. The gauge shown in ( b ) is used when it is desired 

to cut bricks into smaller sections 
of uniform length. These tools are 
used for gauging face brick, but 
may frequently be used for com¬ 
mon brick used in facing walls. 

38. The line, chalk, and 
pencil are familiar but indispens¬ 
able implements. Pieces of leather, 
called leather protectors, are used 
by some mechanics to protect their 
hands when they are required to handle a great number of 
bricks daily. 

39. Method of Laying* Brick.— In connection with the 
laying of brick, certain terms are used. When a brick is laid 
with its length in the direction of the wall, as shown at a in 
Fig. 18, it is termed a stretcher; a brick placed crosswise so 
that its end is exposed in the face of the wall as shown at b 
in big. 18, is called a header. A course of brick may mean one 
horizontal layer of brick or it may mean one horizontal layer 
of brick and one horizontal mortar joint. 

In America, most bricks are laid in what is known as the 
American bond, which is described later in this Section. This 
bond consists of a layer, or course, of headers and four or five 
courses of stretchers, then another course of headers, etc. In 
building brickwork of this kind it is customary to lay the 

























COMMON BRICKWORK 


17 


courses on the outside of the wall first. As many as five or 
six courses are laid before the bricks forming the inside of the 
wall are put in place. These outside courses are laid up 
plumb and level and serve as guides for the courses on the 
inside of the wall. 


40. The first step in laying the wall is to build a portion 
at each end and see that these are plumb and that the courses 
at each end are level with the corresponding courses at the 
other end. 

A mason’s line is then stretched between these ends to serve 
as a guide in laying the brick in between. In Fig. 8 is shown a 
mason’s line c d and the method of attaching it temporarily to 



Fig. 8 


the wall. This is done by driving a nail a into the mortar joint 
and winding the line around this once or twice. The line is 
held taut by tying a piece of brick b to the end. The line is 
secured in a similar manner to the corresponding course at the 
other end of the wall and bricks are laid in between so that their 
upper edges coincide with the line. By this method the wall is 
kept plumb and the horizontal joints straight and level. 

When the work is interrupted for any length of time, the 
outer courses should not be higher than the backing, especially 
where face brick is used, as the mortar joints in the face of 
the wall will dry out too rapidly and the color of the mortar 
will appear different from that in other parts of the face of 
the wall. 














18 


COMMON BRICKWORK 


41 . In Fig. 8 is shown the actual process of laying brick in 
a 16-inch or 17-inch wall. A trowel with mortar on it is moved 



over the wall in the direction of the arrow and at the same 
time is tilted so as to allow the mortar to slide off. This dis¬ 
tributes the mortar over the outer course of brick in the wall. 
The mortar is then spread with the point of the trowel, which is 
drawn through the mortar with a vibrating motion of the hand 
which causes the mortar to form little ridges as shown in Fig. 9. 
A brick is then placed on this mortar bed about 3 or 4 inches 
away from the brick against which it is to be placed, as shown 
in Fig. 9, and is shoved into place as in Fig. 10. The shoving 
movement forces a quantity of mortar up into the vertical 



Fig. 10 


joint e, Figs. 9 and 10, and squeezes out any excess of mortar 
that may be in the joints. 



























COMMON BRICKWORK 


19 


The tipper edge of the brick should coincide with the line c d, 
which is the mason’s line previously referred to. If this edge 
is too high, the brick is tapped down with the handle of the 
trowel or sometimes with the hammer until it is even with the 
line. If the top of the brick is below the line, the brick must 
be taken up and more mortar placed under it. 

\\ hen the brick has been accurately placed, all the mortar 
which has been squeezed out while placing the brick and which 
projects beyond the face of the wall is removed by a stroke of 
the trowel as indicated in Fig. 10. This surplus mortar adheres 



Fig. 11 


to the trowel and is scraped off against the vertical edge of the 
brick as shown in Fig. 11. 

42 . After five or six courses have been laid on the face of 
the wall, the joints are all smoothed with a trowel, then the 
interior of the wall back of these face courses is begun. 

The inside course is first laid in the manner described for the 
face courses and the mortar joints on the inner face of the 
wall are smoothed with the trowel. A bed of mortar is then 
placed between this course and the outer course and bricks are 
placed in the space quite rapidly, as it is not necessary that they 
be exactly placed. Bricks that are slightly chipped, warped, or 
that have slight defects are used in the heart of the wall with 
satisfactory results. Mortar is then filled in between these 
bricks from the top and another row, or course, is placed on top 
of the one just finished. Very often the joints in the interior 
of a brick wall are not completely filled with mortar, and where 








20 


COMMON BRICKWORK 


the wall does not bear a heavy load this kind of work may be 
sufficient. In the case of piers and portions of wall that sup¬ 
port great loads, it is necessary that all the interior joints in 
the wall be well filled with mortar. 

43 . Frequently, instead of laying the bricks on the outside 
of the wall with a shoved joint, as illustrated in Fig. 9, the 
bricks are laid right in place, as shown in Fig. 12, with only a 
small amount of mortar between their ends, such as has been 
scraped off the trowel. This joint should be afterwards filled 
by throwing mortar into the top of it from the trowel. 

44 . Laying Brick in Severe Weather.— When brick¬ 
work is erected in freezing weather, all the materials, as far as 



possible, should be warmed. The brick should be thoroughly 
dry and in addition should be heated. The mortar should be 
warmed by using hot water and heating the sand. The scaffold 
and the wall may be enclosed in tarpaulins, which are large 
sheets of heavy cotton cloth, and inside the tarpaulin enclosure 
fires may be kept burning in salamanders, which are sheet-iron 
cylinders supported on iron legs. 

The work should be carefully protected at night by coverings 
of boards or tarpaulin and should be protected from snow and 
rain until the mortar has thoroughly set. 

Salt is sometimes added to the water with which the mortar 
is mixed, to prevent its freezing until a very low temperature 
occurs. The salt, however, is apt to appear later on the face of 















COMMON BRICKWORK 21 

the wall in the form of a white efflorescence which disfigures 
the wall. 

In very hot weather the brick should be thoroughly wet with 
water sprayed on them from a hose. If this is not done, the 
brick w ill absorb water from the mortar, which will prevent its 
setting. 


SCAFFOLDING 

45. Inside Scaffolding.—In erecting brickwork it is 
necessary to build scaffolding as the work progresses. The 
contractor naturally uses the cheapest type of scaffold that will 
serve his purpose, and will always 
use an inside scaffold instead of an 
outside one if the character of the 
work will permit. The reason is 
that the floorbeams can then be 
used to support the scaffold and the 
scaffold will not have to be built up 
from the ground. 

46. When a simple job of 
brickwork is to be done, such as a 
plain building, the bricks are gen¬ 
erally laid from the inside so that 
the inside scaffold can be used. 

Boards laid upon the floorbeams 
serve as a scaffold for the wall up 
to a height of about 4 feet 6 inches. A scaffold consisting of 
wooden hors.es with planks laid upon them serves for laying 
the upper half of the wall of the story. This process is then 
repeated, the same horses and planks being used over again. 

47. Instead of wooden horses, square wooden frames, 
Fig. 13, braced at the corners, are often used. These are placed 
in an upright position and braced with boards placed diagonally. 
Planks are then placed on top of these frames. 

48. Exterior Scaffolds. —Exterior scaffolding must be 
used when the outside face of a wall is to have an ornamental 
character or be trimmed with cut stone or terra cotta. 


























22 


Fig. 14 






































































































































































































































































































































































































































COMMON BRICKWORK 


23 


I he most common form of scaffolding used by masons is the 
pole scaffold. There are two types of the pole scaffold. 
One type depends partly upon the wall for support and the 
other type is built so as to be self-supporting and independent 
of the building. 

A scaffold that receives some support from the wall is illus¬ 
trated in Fig. 14. This scaffolding consists of uprights or 
poles a, which may be circular in cross-section, but which are 
generally in the form of small timbers, having a cross-section 
of 3 in.X6 in. for a five-story building and never less than 
3 in.X4 in. The poles should be placed about 5 feet away from 
the face of the wall and about 7 feet 6 inches apart on centers. 
They should be firmly supported on the ground, and the lower 
ends should be braced so they will not slip. When they must 
be spliced together to make them longer, they are placed end to 
end and a piece of plank is nailed on each side of the joint as 
shown at b. These splices should not occur in all the poles at 
the same level. Ledger boards c are nailed to the poles to 
brace them horizontally and also to support the putlogs d, which 
sustain the floor of the scaffold. The other end of the putlog 
extends into the wall 4 or 5 inches. The uprights are braced 
diagonally by the braces e and to window frames by the window 
braces /. These latter braces prevent the scaffolding from fall¬ 
ing away from the building. 

What is known as a spring- stay is shown at k. This 
device consists of two boards or planks, the ends of which are 
placed in a hole in the wall and a block is placed between them 
near to the wall. The block causes the boards to spread. The 
spread ends are brought together and nailed to the ledger. 
This action forces apart the ends in the wall so that they obtain 
a firm grip in the wall. The spring stay holds the scaffold 
firmly to the wall. 

A platform g, formed of 2"X10" planks, which lap over each 
other at the ends, is Lid on the putlogs. Foot-boards li are 
nailed on top of the platform against the uprights, also a guard¬ 
rail i is placed at a suitable height. 

The entire structure should be thoroughly braced and well 
nailed with 10- or 12-penny nails. 




24 


Fig. IS 




























































































































































































































COMMON BRICKWORK 


25 


49 . A self-supporting pole scaffold is shown in Fig. 15. 
There are two sets of poles or uprights as shown at a in the 
side view. These are braced together, as indicated at b in the 
front view, as well as in a direction perpendicular to the wall, 
as at c in the side view. The planks of the working platform 
are carried on horizontal pieces which, as shown, do not touch 
the building. Putlogs are not used in this scaffold, as their use 
is likely to disfigure the face of the wall. It is always difficult 
properly to patch up the holes in the wall made by the putlogs, 
and for this reason it is desirable to use an independent scaffold. 
The upper part of the first-story wall is laid from the scaffold d, 
which consists of planks laid on horses. There are two guard 
rails shown at c. A scaffold of this description should not be 
used for a wall more than 100 feet in height. 

50 . A type of scaffold that is used when only one story of 
the wall, such as the cornice story, is required to be built from 
the outside, is formed by extending planks on edge out of the 
window openings and laying a platform upon them. Guard 
rails should be provided as in other scaffolds. 

51 . Suspended Scaffolds.— On tall, skeleton-construc¬ 
tion buildings, suspended scaffolds are used. Steel beams called 
outriggers are supported on the floorbeams of the upper part 
of the frame of the building and project out 5 or 6 feet beyond 
the face of the wall. From these projecting beams the scaffold 
is suspended by means of wire cables. The cables are attached 
to the scaffold by means of devices by which the cable can be 
rolled up and the scaffold thus raised as required. 


BRICK WALLS 


TYPES OP DRICIv WALLS 

52 . Solid Walls. —The brick wall most universally used 
and which is cheapest to construct is the solid wall. This wall 
consists of a solid mass of brickwork with no hollow spaces 
constructed in it. Such a wall is substantial, easy to build, and 
when properly constructed will last for centuries. 






26 


COMMON BRICKWORK 


53 . There are certain disadvantages characteristic of brick 
walls, and these result from the porosity of the brick and 
mortar. Unless a wall is built of good hard-burned brick and 
laid up with a properly proportioned mortar, moisture is likely 
to find its way through it. Some method is, therefore, gen¬ 
erally adopted to prevent this moisture from reaching the inner 
surface of the brickwork, especially when plastering is applied 
directly to the brick. 

54 . One of these methods is to coat the inner surface of 
the wall with a damp-proofing compound which fills the pores 
on the inner surface of the wall and adheres strongly to the 
brickwork. At the same time this compound afifords a good 
key for the plastering. 

Another method is to form the inside 4 inches of hollow 
bricks or 8 inches of hollow tile, but while plastering applied 
directly to these surfaces will hold satisfactorily, the bonding 
courses of the joints are apt to become damp on the inside 
during wet weather. 

55. The best and cheapest method of preventing water 
from reaching the plaster is to fur the walls. This may be 
done by nailing wooden furring strips about 1 inch by 
2 inches in size to the inner face of the wall and nailing wood 
or metal lath to them to receive the plastering. Metal rods or 
furring may be stapled to the walls and metal lath fastened to 
them, or one of the several types of self-furring metal laths 
may be used. Terra-cotta furring may be applied to the entire 
face of the wall, such furring being held in place by the use of 
mortar and nails. 

56. Hollow Walls. —Hollow walls, or more properly, 
double walls, are sometimes built and are intended to keep 
moisture from passing through, and by providing a complete 
separation of one wall from the other, keep the building cooler 
in summer and warmer in winter. Difficulties that largely off¬ 
set their advantages are met with in construction, however, so 
that hollow walls are not often used in the United States. 
The objections to hollow walls are that more ground area is 


COMMON BRICKWORK 


27 


required, thicker foundations are needed, the cost of construc¬ 
tion is increased, and there is no assurance that the two walls 
are better than one solid wall properly furred. 

57 . Party Walls.— A party wall is a wall that sepa¬ 
rates two adjoining buildings and carries the floor and roof 
beams of both of them. The floor loads on party walls are 
twice as great as the load on any outside wall. 

Building regulations in regard to the thickness of party walls 
are based on the span of the joists or width of building, and on 
the height. The specifications of the Committee on Building 
Construction of the National Fire Protection Association 
require all party walls and fire walls to be of solid masonry and 
almost all building codes require solid brick, not only as fire 
protection but to afford the property owner on each side the 
opportunity to insert or hang joists at any desired level or 
place. 

58 . Fire Walls.— The National Fire Protection Associa¬ 
tion has defined a fire wall as follows: “The term Fire Wall 
indicates a wall subdividing a building to restrict the spread of 
fire. In all buildings it shall start at the foundation, be con¬ 
tinuous through all stories and extend at least 3 feet above 
the roof.” 

59 . Panel or Enclosure Walls. —In modern skeleton 
construction, the floor loads in a building are carried on the 
steel or reinforced-concrete frame, and the walls carry no load 
other than their own weight. Such walls are generally sup¬ 
ported upon girders extending from column to column, usually 
at every floor. In this way much thinner walls can be used, 
and valuable space can be saved. 

The New York City Building Code provides that “masonry 
walls supported at each story by girders may be 12 inches thick 
for the entire height of the building.” 

The Chicago building ordinances provide that “If buildings 
are made of fireproof construction, and have skeleton con¬ 
struction so designed that their enclosing walls do not carry the 
weight of floors and roof, then their walls shall be not less 
than 12 inches in thickness.” 





2S 


COMMON BRICKWORK 


60. Curtain Walls. —Following is an extract in regard to 
curtain walls from the New York City building laws: 

-iii tiii “Curtain Walls. Non-bear- 





4 inches for brick. The 
space is also necessary to 


ing walls built between piers or 
metal columns shall not be less 
than 12 inches thick for the 
uppermost 60 feet of height, 
increasing 4 inches in thickness 
for each next lower section of 
60 feet.” Curtain walls are not 
supported by beams, but rest on 
suitable footings supported on 
the foundation soil. 

61. Veneered W alls. 

Frame houses are frequently 
incased in a 4-inch veneer of 
brick, separated from the wood 
by a 1-inch or a 2-inch air 
space. Veneered walls are 
generally somewhat cheaper 
than those built of solid brick. 
FI o u s e s constructed in this 
fashion are warmer in winter 
and cooler in summer, and are 
also less likely to catch fire 

J 

from outside sources than are 
ordinary frame buildings. 

62. In building a house 
with veneered walls, the foun¬ 
dation must project far enough 
beyond the line of the studs to 
carry the brickwork that is put 
on later. This requires a pro¬ 
jection of 1 inch for sheathing, 
1 or 2 inches for air space, and 

or 2 inches allowed for an air 
accommodate the mason’s finders 

o 







































































































































































COMMON BRICKWORK 29 

when he is laying the brick, and is frequently called a finger 
space . 

Care must be taken to construct the frame in the best man¬ 
ner, for the brick veneer carries absolutely no part of the build¬ 
ing except its own weight, and in fact has to be tied to the wood 
framing for support. After the frame is up it should be 
sheathed diagonally and the sheathing should, as a rule, be 
covered with tar paper or other waterproof material on the 



outside before the bricks are laid. The sheathing is omitted in 
a very cheap form of construction such as is shown in Fig. 16 
(a). This form of construction is not to be recommended, 
however. The tar paper is omitted in Fig. 17 for the sake of 
clearness. All the framing timber, particularly the sills, should 
be as dry as possible, and the frame must be perfectly plumb 
and straight; if not, the brick veneer will not lay up properly. 

The brick veneer is usually tied to the diagonal sheathing or 

246—3 



























































so 


COMMON BRICKWORK 


to the studs with metal ties. The wire tie, shown in Fig. 16 ( a) 
and (c), is most generally used, though a tie made of No. 16 
iron, 1^ inches wide, with the end turned up, as shown in 
Fig. 16 ( b ), gives satisfactory results. The ties are generally 
placed on every other brick in every fifth course of brickwork. 

03. Fig. 17 shows a section through part of the foundation 
of a veneered building and the principal features of its con¬ 
struction. At a is shown the stone foundation wall, project¬ 
ing 6 inches beyond the diagonal sheathing b; the 4"X6" sill 
is shown at c, the 2"X10" floor joists at d, and the air space 
between the brickwork and the sheathing at e. The 4-inch 
brick-veneer wall is shown at f, and the wire tie at g; the stone 
window sill is shown at li, the 2"X4" studding at k, the lathing 
at l, the flooring at m, and the window frame at n. 

Due to the fact that any stability which a 4-inch brick veneer 
receives is dependent upon metal ties, which may rust, attached 
to a wooden building which may vibrate and will burn, this type 
of construction is not to be recommended, especially for any 
height above two stories. 

04. Veneering* on Hollow Tile. —Brick, especially face 
brick, may be used as a veneer on hollow building tile or 
back-up blocks. A wall of this description is generally damp- 
proof, and plastering can be applied to the inside face of the 
terra cotta without the danger of dampness affecting it. Such 
walls will be more fully described later in the Section on 
Hollow Tile. 


THICKNESS OF WALLS 

05. The thickness of walls in brick masonry is a matter 
that cannot be determined by calculations. Experience must 
be followed and also the regulations laid down in the building 
codes of different cities. The latter is the better plan, as the 
stipulations given in these codes are the result of experience of 
many men, and there are thousands of buildings to show the 
successful application of the rules given in these codes. 

00. According to the New York City Building 
Code. —The New York Building Code makes the following 




COMMON BRICKWORK 


31 


provisions for structures where the walls are entirely of brick 
and support the floors and roofs, and where no steel columns 
or beams are built into the walls : 

Residence Buildings. —Except as otherwise provided, the thicknesses 
of brick walls of residence buildings hereafter erected shall be not less 
than the following: (a) When over 75 feet in height, 12 inches for the 
uppermost 25 feet, 16 inches for the next lower 35 feet, 20 inches for the 
next lower 40 feet, with a 4-inch increase for each additional lower 
section of 40 feet; ( b ) when not over 75 feet in height, 12 inches for the 
uppermost 55 feet, and 16 inches below that. 

Public and Business Buildings. —Except as hereinafter provided, the 
thickness of masonry (brick) walls of public and business buildings 
hereafter erected shall be not less than the following: 

(a) When over 75 feet in height, 16 inches for the uppermost 25 feet, 
20 inches for the next lower 35 feet, 24 inches for the next lower 
40 feet, and increasing 4 inches for each additional lower section of 
40 feet. 

(b) When over 60 feet and not over 75 feet in height, 16 inches for 
the uppermost 50 feet, and 20 inches below that. 

( c ) When over 40 feet and not over 60 feet in height, 12 inches for 
the uppermost 20 feet, and 16 inches below that. 

(d) When not over 40 feet in height, 12 inches throughout. 

Increased Thickness When Required. — (a) Every bearing wall with 

face brick bonded with clip courses or ties, and every bearing wall faced 
with ashlar, shall have a total thickness of at least 4 inches more than 
otherwise required unless the ashlar is at least 8 inches thick in every 
alternate course and bonded to the wall. 

( b ) When the clear span between bearing walls is over 26 feet, such 
walls shall be increased 4 inches in thickness for every 12| feet or part 
thereof that said span is over 26 feet. 

( c ) All walls over 105 feet long between cross-walls or proper piers 
or buttresses, shall be increased in thickness over the minimum require¬ 
ments at least 4 inches for every 105 feet, or part thereof, over 105 feet 
in length. 

(d) If the horizontal section through a bearing wall shows more 
than 30 per cent, area of flues and openings, such part of the wall where 
the excessive openings exist shall be increased 4 inches in thickness over 
minimum requirements for every 15 per cent, or fraction thereof, of flue 
or opening area in excess of 30 per cent. 

General Reservations. —Nothing in these laws shall prevent the use 
in any wall of the same amount of material in piers and buttresses as is 
required for the thickness prescribed. 

The unsupported height of any wall or part thereof shall not exceed 
20 times the thickness of such unsupported part, unless reinforced by 
adequate cross-walls, buttresses, or columns. 







32 


COMMON BRICKWORK 


67. According* to tlie Chicago Building Ordi¬ 
nances.— The ordinances of Chicago group buildings into 
several classes and specify certain conditions that apply to 
these different classes. Where the walls of the buildings are 
entirely of masonry and support the floors and roof, the fol¬ 
lowing general regulations are prescribed : 

Brick, stone, and solid concrete walls, except as otherwise provided, 
shall he of the thickness in inches indicated in the following table: 


Number of 
Stories in 
Building 

Story 

Basement 

I 

2 

3 

4 

5 

6 

7 

8 

9 

IO 

II 

12 

Thickness of Wall, in Inches 

One. 

12 

12 












Two. 

Three.... 
Four. 

16 

16 

20 

12 

l6 

20 

12 

12 

16 

12 

16 

12 









F i ve. 

24 

24 

24 

24 

28 

20 

20 

16 

16 

16 








Six. 

20 

20 

20 

16 

16 

16 







Seven.... 
Eight.... 
Nine. 

20 

24 

24 

28 

20 

24 

24 

28 

20 

20 

24 

24 

24 

28 

20 

20 

20 

16 

20 

20 

16 

16 

20 

16 

16 

16 

16 

16 

l6 




Ten. 

28 

24 

24 

24 

24 

24 

24 

20 

20 

20 

l6 

l6 



Eleven. . . 
Twelve . . 

28 

32 

28 

28 

28 

28 

20 

24 

20 

20 

20 

20 

l6 

20 

l6 

l6 

l6 

l6 

l6 


There are modifications in these thicknesses that may be 
made under certain conditions, and when building where this 
code is in force a copy of the ordinances should be obtained 
and carefully followed. For instance, certain provisions are 
made for the use of 8-inch or 9-inch walls in dwellings and 
other small buildings, and these and other provisions must be 
complied with where such laws are in force. 














































COMMON BRICKWORK 


33 


BOND IN BRICKWORK 

68. Necessity for Bond.— To build a strong, substantial, 
and solid wall with such small pieces of material as bricks, 
requires a careful arrangement of the bricks in the body of the 
wall so that they shall be tied together and form a cohesive 
mass of masonry. Tying the bricks together is done partly by 
good mortar and largely by proper bonding. Bonding: may 
be described as the process of laying bricks so that one brick 
shall rest on parts of two or three bricks below it. The bond in 
a wall is the result obtained by bonding. Brickwork that is not 



properly bonded is shown in Fig. 18. By placing the brick in 
this manner, the wall is merely a series of piers that abut each 
other on the lines c, d and have no bond or union between 
them other than that obtained by the adhesion of the mortar. 

The object of the standard bonds, that will be described 
presently, is to tie the wall together both longitudinally, or in 
the direction of the length of the wall, and transversely, or in 
a direction perpendicular to the face of the wall. The best 
brickwork is that in which the bricks are most thoroughly tied 
or bonded together, both lengthwise and crosswise, as well as 
vertically. 



























34 


COMMON BRICKWORK 


69. Terms Used in Bonding:.— When brick are laid 
lengthwise in the face of a wall, as at a in Fig. 18, they are 
termed stretchers. When placed crosswise so that their ends 
are exposed in the face of the wall, as at b, they are called 
headers. A course means a horizontal layer of brick or one 
horizontal layer of brick and one horizontal mortar joint. 
Parts of bricks, that are made by cutting the whole brick, are 
called hats or closers. The different bats used in brickwork 
are shown in Fig. 19. A whole brick is shown in (a). When 
a brick is cut longitudinally, as in (b), on the line a b, each 
half is called a queen closer. It is difficult, however, to cut a 
brick in this manner, hence it is first cut on the line c d e and 






each half is cut along the line a b. When a brick is cut as in 
(c), it is called a king 1 closer. When one-fourth of a brick is 
cut off as in (d) the remainder is called a three-quarter hat. 
In 0) is shown a half hat and in (/) a quarter hat. 
A closer is a bat used to fill up a space near the end of a wall, 
resulting from the longitudinal bond used in the wall. Closers 
are illustrated in Fig. 20 at c. 


70. Bonding is accomplished by lapping one brick over por¬ 
tions of two or more bricks in the course below. This process 
is often referred to as breaking joints. The vertical joints 
should not come one above the other in the face of the wall as 
shown in Fig. 18, but should alternate as shown in Fig. 20. 
This is done systematically so that the vertical joints shall 










COMMON BRICKWORK 


35 


occur in plumb lines, lhe vertical joints in one course should 
be kept perpendicular, or directly over those in the second 
course below. 

I he joints in both faces of the wall should be directly oppo¬ 
site each other. This arrangement of the joints in the top of 
the wall is shown in Figs. 18, 21, 22, etc. 


STANDARD BONDS 

41. In the course of time there have been developed several 
standard methods of bonding brickwork such as the English, 
Flemish, American, Running, etc. bonds. 


72. English Bond.— lhe English bond is probably the 
best and strongest method of bonding brickwork. In this 



bond, header and stretcher courses are laid alternately, as 
shown in Fig. 20. Joints are broken in the longitudinal bond 
courses by the use of quarter-bat closers, marked c. This is 
without doubt the best and simplest bond to use in all work 
where strength is required, as by its use a complete and thor¬ 
ough transverse bond is formed. It will be observed that the 
heart of this wall, which is about 16 inches thick, consists 
entirely of headers, and that the joints of the header course, as 
at a, are well bonded by the headers b of the stretcher course. 

73. The wall shown in Fig. 20 has only two different 
courses. The arrangement of the bricks in these courses is 












3G 


COMMON BRICKWORK 


shown in Fig. 21 in courses A and B. By studying these plans 
in connection with Fig. 20 there should be no difficulty in 
understanding the construction of the wall. At c are shown 



Course A Vertica/ Section yy 



Fig. 21 

queen closers; at d, half-bats; and at c, three-quarter bats. 
These latter are used in forming the end / of the wall. 

In the vertical section through the wall taken through g g 
are shown the cross-ties formed by the bricks li lapping over 


































































































































































COMMON BRICKWORK 


37 


the bricks i. T he perspective view shows the arrangement of 
the bricks in the face of the walk The closers are shown at j 
and the end of the wall at /. 

Flemish Bond.— The Flemish bond is one in 

which each course is composed of alternate headers and 
stretchers. The method of laying the bricks in this bond is 
illustrated in Figs. 22 and 23. Bats a and b are used at the 
corners of the walls and at c on the interior of the wall. In 
this example the headers and stretchers on the inner face of 
the wall are exactly opposite those on the outer face, and the 
wall is said to be built in double Flemish bond. The ver¬ 
tical section is taken through e e on the plans of the courses 



A and B and shows the bond. The perspective view shows the 
appearance of the bond in the face of the wall and the jamb /. 

75. American, or Common, Bond.— The bond most 
extensively used in the United States is known as the Amer= 
ican, or common, bond. It is, in fact, a modification of 
the English bond. Instead of making every other course 
of brick a header course, as in the English bond, every fifth, 
sixth, or seventh course is made a header course in the 
American bond, with stretcher courses in between. This con¬ 
struction is illustrated in Fig. 24. Plans of the different courses 
are shown in Fig. 25, in which (a) and (b) are the courses 
that form the cross-bond, and (c) and ( d ) the stretcher 
courses in between. The arrangement of these courses is 
shown in the vertical sections (/) and (g). 
















Course B. 


Perspective View 


Fig. 23 




38 
























































































































































































39 


Fig. 25 






























































































































































































































40 


COMMON BRICKWORK 


The bond shown in (/) is formed by the two header 
courses b placed at the same level on the outside and inside 
faces and a course a lapping over both headers. This treatment 
brings the heading courses at the same level on both sides of 
the wall. 

In ( g ) is a slightly different arrangement which is often 
used. In this case the header course on one side of the wall is 
lower than the header course on the other side. 

The courses (a), ( b ), ( c ), and ( d ) are laid out according 
to the section (/). The arrangement of the bricks in the face 
of the wall is shown in (c). This form of bonding makes a 
wall that can be quickly and therefore cheaply built. 

76. American bond is generally used in the United States 
not only for building walls of common brick, but also for back¬ 
ing up terra cotta, stone, and face brick. In fact the backing up 
is the real wall that not only supports the floor and roof loads, 
but also the weight of the facing. 

The New York building laws require that every sixth course 
shall be a header course; that is, that five courses of stretchers 
must come between two courses of headers. For factory and 
warehouse purposes, where the walls have to sustain heavy 
weights, it is better to have every fourth course a header 
course, thus giving three courses of stretchers between the 
header courses. 


BONDING FACE BRICIv 

77. Stretcher or Running- Bond. —When a facing of 
brick is applied to a wall of common brick it is necessary to tie 
the facing firmly to the backing, or common-brick wall. This is 
done in different ways. When the facing is in running or 
stretcher bond there are no headers appearing in the face of the 
wall. In this case galvanized metal ties are generally used as 
shown in Fig. 26. 

78. Face Bonds. —English and Flemish as well as other 
ornamental bonds are often used as facings only and are 
secured or bonded to a wall that is laid up in American or 
common bond. This can easily be done by extending some of 



COMMON BRICKWORK 


41 


the numerous headers of the face bonds into the backing and 
thus securing an ample tie. The remaining headers will be 
composed of half-bricks or bats. 

79. Metal Ties for Brickwork. —Fig. 26 illustrates the 
method of bonding in face brick with steel or galvanized-iron 



Fig. 26 


wire. These wire ties b are twisted at the ends, and hold 
together the inside and outside courses a and c, as shown. 
They are laid in every sixth course of brick. 

A still better method of tying front brick to the common 
brick in the rear of the wall is by the use of galvanized steel 



ties from to s inch thick, and having some of the metal 
punched out. The brick may be brought down to a very dose 
joint, and the clinching edges make a very firm and satisfac- 




































42 


COMMON BRICKWORK 



tory binder. Fig. 27 shows the application of these bonding 
strips. Here, a is the pressed-brick facing, b the common brick 

in the rear of the wall, and 
c the steel ties bonding the 
pressed brick to the com¬ 
mon brick. 

Similar ties can be used 
for tying a new wall to an 
existing wall to increase its 
strength. The tie is bent 
near the middle, as shown 
at a in Fig. 28, and is nailed 
to the old wall with pointed 
wrought-iron nails, shown 
Fig. 28 at b. These nails have 

large flat heads made^especially for this work, and are of 


sufficient size to make 
a firm connection for 
the new courses c. 

Other forms of 
metal ties that are on 
the market are shown 
in Fig. 29. In using 
such ties it is gen¬ 
erally advisable to use 
those that are sold in 
the local market. 










_ = := 
= = = 




BONDING HOLLOW 
WALLS 

80. Before the in¬ 
troduction of metal 
ties, the bond between 
the two walls which 
form the hollow or 
double wall was accomplished with brick which were embedded 
in both walls and extended between them, tying them together. 











































































































































COMMON BRICKWORK 


43 


This method was very expensive, as it required considerable 
cutting of brick. It also reduced the effectiveness of the 
hollow wall, as it provided places in the bonding brick through 
which dampness might pass. 

81. Bonding' With Metal Ties.—Bonding hollow walls 
by the use of metal ties is the cheaper and probably the better 
method, provided the ties are thoroughly protected from cor¬ 



rosion by galvanizing. These ties make the hollow wall effec¬ 
tive, as the ties will not carry moisture to the inner wall. 

At a. Fig. 30, is shown a 4-inch wall; at b, the air space; 
at c, the inner 8-inch wall; and at d, the metal ties. It should 
be said that hollow walls are not built very frequently, as the 
same results can be obtained at less cost by using hollow terra¬ 
cotta tile, called back-up tile, with a veneering or facing of 
brick. 


. BONDING WALLS AT ANGLES 

82. In building brick walls, it is necessary that the angles 
in the walls be properly bonded. When the two walls forming 
the angle are carried up at the same time, the bonding at the 
corners is easily effected; if, however, one wall is built first, due 
to a delay in getting materials required for the other wall, 
particular care must be taken that the two parts will bond 
together properly. 

In such cases, the wall first built is generally left toothed, as 
shown in Fig. 31. 












44 


COMMON BRICKWORK 


In order to unite the two walls more firmly, anchors made 
of f"X2" wrought iron, with one end turned up 2 inches 
and the other turned around a f-inch bar, should be built into 
the side wall about every 4 feet in height, as shown at b, 



Fig. 31 


Fig. 31. These anchors should be long enough to extend at 
least 12 inches, or the depth of one and one-half bricks laid the 
long way, as shown at a, into the side wall, and the center of 
the f-inch bar should be about 8 inches from the back of the 
front wall. 




























COMMON BRICKWORK 


45 


JOINING NEW WALLS TO OLD WALLS 

88. In joining a new wall to an old, a groove should be cut 
perpendicularly in the old wall, usually the width of a brick, so 
as to make a joint; this is called a slip joint. 

This method of bonding is shown in Fig. 32. At a is shown 
the groove or chase cut where the new wall is to enter in the 
old wall; c is the new wall, and d the old wall. 


OPENINGS IN WALLS 

84. Openings in Solid Walls. —When a brick wall con¬ 
tains door and window openings, their location and relative 
position should be very carefully 
considered, not only with regard 
to convenience and symmetry, but 
also with regard to their effect on 
the strength of the wall. When 
walls are broken frequently by 
windows and other openings, 
cracks are more likely to occur 
than when the wall is plain and unbroken. This is owing to the 
unequal pressure on the wall. If walls are well bonded and 
anchored, the danger of cracks will be reduced to a minimum. 
When possible, the window openings in the different stories 
should be placed directly over one another, for appearance, as 
well as to prevent cracks in the wall, or in the arches, lintels, or 
sills of the windows. 

Unless absolutely necessary, the placing of windows under a 
pier or directly over a narrow mullion should be avoided. When 
such a design must be used, brick arches or metal beams, or both, 
should be built in if the span is great or the arch a flat one. 

In any bearing wall carrying the ends of floorbeams, the 
combined horizontal area of openings should not be more than 
one-third the total horizontal area of the wall, unless the thick¬ 
ness of the wall between the openings is increased by the use of 
pilasters, or buttresses. 



246-4 






46 


COMMON BRICKWORK 


85. Relieving Arches and Lintels. —Openings may 
be spanned at the tops by means of relieving arches or by lintels 
formed of rolled steel shapes. In Fig. 33 is shown a section 
and an elevation of a brick relieving arch a which is built upon a 
wood center b. This arch supports the wall and the opening at 
the rear of the stone lintel c. The brick laid in the manner 

shown at a are called rowlocks, 
and arches made of two or 
more rows of rowlocks are 
called rowlock arches. 

Lintels may be made of 
rolled-steel shapes as shown in 
Fig. 34. In (a) is a stone lintel 
that shows in the face of the wall. In this case it is 4 inches 
thick and supports the face of the wall above. If the opening 
is wide the lintel should be supported on an angle as indicated 
at b. The inner 8 inches of the wall are supported by means of 
two angles c and d. The end of the opening is shown at the 
right and the angles are indicated by the dotted lines. The 
angles should have a 4-inch bearing on the wall at each end. 

In (b) is shown a similar design for a lintel of a 16-inch 
wall. This opening has also a 4-inch stone lintel and requires 
three additional angle irons to support the inner 12 inches of 




Fig. 34 




i — m 



• 






—i— 

i 



i 

i 




i 

—i- 

(C) 

i 

ii 



the wall. The end of the open¬ 
ing is shown at the right. 

In (c) is a lintel over a wide 
opening. In this example an 
I-beam a and a channel b, to 
which is attached an angle c, are 
bolted together by means of the 


bolt d, to form the support for the wall. 





























































































































































































































COMMON BRICKWORK 


47 


BRICK ARCHES IN GENERAL 

86. Arches should be laid up in cement mortar by care¬ 
ful and experienced workmen, or otherwise there is danger of 
the arches failing and letting down the weight imposed on them. 

87. Definitions of Terms. —The following definitions 
of terms used in connection with arches are given. They may 
be readily understood by referring to Fig. 35. 

Span. —The distance between the abutments, as shown at 
a b. The word span is also used to mean the material con¬ 
struction that spans, or covers, an opening or a gap. 

Springer, or Skewback. —The stones or bricks that lie 



Fig. 35 


immediately on the imposts, as at c, c, from which the aich 
proper springs. 

Spring Line. —A line drawn through the points where the 
arch intersects the abutments, or where the vertical suppoits of 
the arch terminate and the curve begins, as shown at c d. 

Intraclos. —The lower concave surface of the aich, formed 
by the under sides of the bricks, although considered by some 
authorities to be the concave line at the edge of the under side 
of the bricks. 

Soffit. —The lower surface of the arch, or the intrados. 




































































































































48 


COMMON BRICKWORK 


Extrados.— The upper convex surface of the arch formed 
by the outer sides of the bricks in the arch; also, considered by 
some authorities as the convex line of the curve of the outside 
of the arch. 

Rise.— The perpendicular distance from the spring line to 
the highest point of the intrados. 

Arch Ring-.— The arch itself, contained between the 
intrados and the extrados. 

Crown.— The highest portion of the arch. 

Haunches. —The portions of the arch included between 
the crown and the skewbacks. 

Tympanum.— The space between the spring line and the 
intrados. 

Spandrel.— The triangular wall space included between 
the extrados, a horizontal line drawn through the top of the 



extrados, and a vertical line drawn through the lower extremi¬ 
ties of the extrados. This term is also applied to the space 
between two arches in a series of arches. The spandrel is 
shown at z x y. 

Spandrel Filling.— The brickwork filling the spandrel. 

Rowlock.— One of a series of arch courses, or rings, shown 
at m, m. There is no bond between these rings other than that 
afforded by the adhesion of the mortar. 
























































COMMON BRICKWORK 


49 


88. Construction of Arches. — When semicircular 
arches are constructed of common bricks, the bricks are laid 
close together on the intrados, with wedge-shaped joints on the 
face of the arch; that is to say, the mortar joints are wider at 
the upper surface of the brick ring than at the lower surface, so 
that there is more mortar at the top of the joint than at the 
bottom. 

Fig. 36 shows a semicircular arch consisting of two rings of 
rowlocks. These arch bricks are all laid as headers, and the 
long edges of the bricks show in the soffit of the arch. The 
increase of the thickness of the mortar in the joints is shown in 
the illustration. 

89. Arches made of common brick are generally rowlock 
arches, and the difference in thickness of the joint in a distance 
of the width of one brick is not objectionable. An arch formed 
of bricks set with the length in the direction of the radius 
would require a decidedly greater thickness of joint toward 
the extrados than at the intrados. It is sometimes desired to 
use brick in this manner in connection with rowlocks in order 
to form a bond in the arch. In such cases it is necessary to 
have the bricks made to a radius, or wedge-shaped. Such 
bricks are called gauged or shaped bricks. 

90. Gauged Bricks. —Fig. 37 shows a semicircular arch 
constructed of ganged, or shaped, bricks. The gauging, or 
shaping, may be accomplished by laying out the arch ring on a 
floor, and cutting, rubbing, or grinding the bricks to a certain 
gauge, or pattern, so that each brick will fit exactly in the 
place chosen for it; and all the mortar or radial joints will be 
of the same thickness throughout. This process is, however, 
expensive, and where there are many arches the brick should be 
molded in the required shape when manufactured. 

In the example shown in the illustration, the space under 
the arch is filled by a brick wall supported on a bluestone 
lintel. This allows the bronze doors underneath to be made 
square on top. 

As seen by the illustration, the extrados of the arch is 
stepped into horizontal steps. This is done so that the bricks 









F ig- 37 


50 
























COMMON BRICKWORK 


51 


in the wall will not 
have to be cut down 
to a knife edge in 
order to make them 
fit the work. 

When the reveal, 
or space between a 
window or door 
frame and the outside 
of the wall, is only 
4 inches, gauged- 
brick arches do not 
usually have any 
bond in the body of 
the wall except where 
metal ties are used; 
therefore, the bricks 
in the arch should be 
laid with great care 
and accuracy. 

The class of work 
shown in the illustra¬ 
tion is not often done 
in common brick, but 
is sometimes required 
in that material. The 
illustration shows the 
forms of bricks that 
will be required in 
such cases. 


CHASES AND FLUES 

91. Vertical 
grooves called chases 
and flues are fre¬ 
quently built in brick 
walls to receive 
plumbing, gas or heat 




Fig. 38 





























































52 


COMMON BRICKWORK 


pipes, etc. The building laws in some cities limit the num¬ 
ber and size of chases that may be used in brick walls. For 
instance, the ordinances in force in New York City require 
that pipe chases shall not extend into any wall for more than 
one-tlnrd of its thickness and shall be not more than 4 feet in 
length measured horizontally. In the same ordinances, the 
areas of chases are counted in the areas of openings. 

92. Fire-Stops.—Brickwork may be used to advantage 
as fire-stops to prevent the passage of flames from one floor 
to another back of the plastering. Brick walls are generally 
furred 1 inch, and this space, if continuous from floor to floor, 
permits the rapid spread of flames through the building. 

Fig. 38 indicates a method of 
corbeling out the wall at the 
floor joists so as to close 
entirely the space between 
the wall and the plaster. At 
a in (a) is shown a wall of 
uniform thickness with the 
brick corbeled out at b for a 
fire-stop. A furring strip c 
makes a close joint with the 
cross-furring strip d. In ( b ) 
the brickwork sets back 4 
inches, as the wall decreases 
in thickness at that point, as 
at a, and b is a joist parallel to the wall. The wall should be 
carried up the full thickness to the top of the joists, and this 
will close all passages from floor to floor back of the plastering. 

Where fire or party walls occur, the joists or beams should 
not be placed directly opposite each other, but should be 
staggered, as shown in Fig. 39. For adequate protection not 
less than 6 inches of brickwork should separate the ends of 
wooden joists. In Fig. 39 a represents a 12-inch wall sup¬ 
porting 2-inch joists on 16-inch centers. The joists b bear 
4 inches on the wall and their ends are separated about 
7J inches. With 3-inch joists similarly placed the ends of the 

















COMMON BRICKWORK 


53 


joists would be separated about 6J inches. Particular care 
should be taken to fill all joints in the brickwork with mortar, 
as unless this is done fire will find its way through from the 
end of one joist to the end of the other. In some cases it is 
difficult to secure 6 inches of brickwork between the ends 
of the joists, and in some cases steel beams may be used to 
secure the proper fire protection. 


BACKING UP 

93. As has been stated, common brickwork is frequently 
used in backing up stonework, terra cotta, and face brick. 
When this work is to be done, the stonework and terra cotta 
should be designed so that the heights of the courses shall be 
equal to the height of a definite number of brick courses, in 
order that the anchors or metal ties can extend back into the 
wall properly. For instance, with a customary size of brick, 
one course is counted as measuring 2\ inches. The stone or 
terra cotta should be laid out in courses that are multiples of 
2\ inches in height. For instance, stone or terra-cotta courses 
should be made 7\, 10, 12J, 15, or 1 7\ inches in height. 

When a wall is faced with face bricks of other size than the 
common bricks used for backing, if the joints of the face brick 
are kept fine and those of the common brick thick, or vice 
versa, the courses will work out to the same height and permit 
of easy bonding every five to seven courses. As some Building 
Codes require frequent bonds, their provisions should be ascer¬ 
tained and bricks selected accordingly. 

The same precaution should be taken in designing stone 
quoins, such as are used at corners of walls. The quoins 
should be designed to be a certain number of courses in height 
so that the bed joints of the stone will coincide with the joints 
on the brickwork. 


EFFLORESCENCE 

94 . Very often, on buildings of stone or brick, more par¬ 
ticularly the latter, white stains will appear on the surface of 
the walls after a few days of wet weather. These stains are 




54 


COMMON BRICKWORK 


called efflorescence, and are due to certain soluble sub¬ 
stances in the brick or mortar, or both. Carbonate of soda 
appears most frequently on new walls, and is due to the action 
of the lime in the mortar upon the silicate of soda in the bricks. 
Silicate of soda seldom occurs in bricks unless a salt clay is 
used in making the bricks. Sulphate of magnesia is formed 
when the clay contains pyrites, or when sulphurous coal is 
used for burning. 

Water may reach the interior of the wall through absorption 
by the brick, through cracks and unfilled joints in the brick¬ 
work, through joints in the upper surfaces of copings or pro¬ 
jecting courses, or from leaking or overflowing gutters and 
leader pipes back of the wall. When once the surface of the 
wall is penetrated, the moisture follows the joints and per¬ 
colates to lower levels and to the outside surfaces, finally 
depositing the soluble substances by evaporation as stains or 
efflorescence. 

Efflorescence may be prevented by the selection of impervi¬ 
ous brick free from soluble materials, by filling all joints with 
mortar, by providing the upper surfaces of copings and pro¬ 
jecting courses with overhanging coverings having drips, and 
by the proper design and maintenance of gutters and leader 
pipes. 

E T sually it is possible to remove efflorescence by washing the 
walls with a dilution of muriatic acid in 20 parts of water, 
which must be afterwards washed off with clean water. Sev- 
veral preservative coatings are designed to be applied to the 
walls after they are cleaned and dried. These preparations, by 
closing the pores in the brickwork, prevent the absorption of 
moisture. To be permanently effective, however, several coats 
must usually be applied, followed by additional coats at 2- or 
3-year intervals. 


COMMON BRICKWORK 


55 


HANGERS, ANCHORS, ETC. 


05 . The use of joist and girder hangers, etc. simplifies 
greatly the work of framing, both for house and mill construc¬ 
tion. With these hangers and anchors, a good and firm bear¬ 
ing may be had in brick walls. The chief requisite of a good 
hanger is that it shall hold firmly to the wall and at the same 




time hold firmly to the joist. Fig. 40 illustrates four styles of 
hangers used to support joists and beams against brick walls. 
In none of these styles does the joist enter the wall, but rests 
in the socket; the top of the hanger being built into the wall. 






































































































































































































































56 


COMMON BRICKWORK 



In the hangers shown in ( a ) and ( b ), the joist is held in 
place by one or two spikes or lagscrews driven in through the 
hole a of the hanger and into the wood. In the hangers shown 
in (c) and (d), there is a ridge, or lug, b on the hanger. A 
notch is cut across the bottom of the joist and the ridge of 

metal fits into this 
notch. The hangers 
in (a), (b ), and ( d ) 
are made of sheet 
steel stamped and 
bent into shape, while 
that shown in (c) is 
of cast steel. The 
hanger shown in (a) 
is known as a Van 
Dorn hanger; the 
one in ( b ) is a Lane 
hanger; and those in 
(r) and ( d ) are 
Duplex hangers. 
These hangers also 
act as anchors, as the 
end of the beam is 
held from moving 
horizontally either by 
spikes or by the lugs 
of the hangers. At 
the same time if the 
middle of the joist 
should fail and drop 
by overloading or by 
fire, the end of the joist would easily fall from the hangers 
shown without injuring the wall. 


Fig. 41 


96 . In Fig. 41 is shown a wall plate that is used for wooden 
beams or girders that extend into the wall. In (a) is shown 
the bearing plate with the lug at a and the flange b which turns 
up and down into the wall. The beam is usually finished with 
















































COMMON BRICKWORK 


57 


a bevel cut on the end, known as a fire-cut. This cut allows 
the beam to fall out of the wall without injury to the wall. The 
fire-cut is illustrated in (&). 

07 . In Fig. 42 are shown the four forms of iron anchors 
that are used for fastening beams in brick walls. The one 



shown in ( a ) is made of £"X1}" iron, about 2 feet long; the 
end built in the wall is made of a 9"Xf" rod with the end of 
the anchor bent around it. 

The anchor in (b) is made of 2"X 1 y / iron, 2 feet long; the 
end that goes in the wall is cut as shown, and about 4 inches is 



Fig. 43 


turned at right angles to the anchor; the other end is twisted 
so that it can be nailed to the side of the joists. 






























































































































































58 


COMMON BRICKWORK 





An anchor that runs entirely through 
a wall is stronger than one that is sim¬ 
ply embedded in a wall. On the other 
hand, the end of an anchor on the out¬ 
side of a building makes an unsightly 
appearance. In warehouses and in 
back walls of buildings, however, when 
neat appearance is a secondary con¬ 
sideration, an anchor like that shown in 
(c) is used. It is made of lf"XJ" 
iron, 2 feet 6 inches long, and has a 
plate of 2"X4"Xi" iron forged on the 
outer end. This style of anchor may 
also be used in the middle of a wall in 
the same manner as those shown in 
(a) and ( b ). 

In (d) is shown probably the strong¬ 
est form of anchor. This style of 
anchor is made by flattening out a J-inch 
bolt so as to make a 2"Xi" portion to 
spike to the joist, and it is provided 
with a 5-inch cast-iron washer. A nut 
is placed on the outer side of the washer 
so that the anchor may be tightened up 
if necessary after the walls are built. 

Anchors should always be spiked to 
the side of the joist or girder at or 
below the middle, as shown in the figure. 

Fig. 43 shows the method of anchor¬ 
ing joists to walls where the joists and 
the walls run parallel. The anchor, let 
into the floor joists as shown at a, is 
provided with a washer b, and should be 
long enough to run over two or three 
joists, and 8 inches into the wall in order 
to give proper stiffness. The floor 
joists are shown at c, and the 12-inch 
brick wall at d. 


(e)mr 

Fig. 44 


















COMMON BRICKWORK 


59 


08 . Fig. 44 illustrates common forms of ties for anchor¬ 
ing I beams, channels, etc. to brick walls. Ordinary wall 
anchors are shown in 
(a), (b), (c), and ( d ), 
while in ( c ) is repre¬ 
sented a tie-rod anchor 
running through the 
wall, to be used when 
the beam is run parallel 
to the wall. 

Steel beams are gen¬ 
erally supported on 
steel templets that are 
set in the wall. These 
templets, shown at a in 
(a) and (b), should be 
made large enough to Fig< 45 

distribute the load over a sufficient surface of brickwork so 
that the brickwork will not be crushed under the load. 



99 . Attaching* Furring, Grounds, Etc. to Brick 

Walls.— In most buildings it is 
necessary to attach wood or 
metal furrings, grounds, bucks, 
etc., to brickwork, and there are 
various methods used for this 


purpose. 

Where the interior of the wall 
is to be furred with wood furring 
to receive lathing and plastering, 
common lath are laid between 
the bricks every few joints as 
shown at a in Fig. 45. They are 
held in place firmly by the brick 
and afford nailing for the fur¬ 
ring. Wood should not be in- 
serted in chimney walls and breasts, but metal furring and 
lath should be used, the furring being attached to wire loops 



Fig. 46 


































60 


COMMON BRICKWORK 


or other devices built in the brickwork. Nails should never 
be driven into a chimney wall less than 8 inches thick, as they 
are liable to break out the mortar on the inside and render the 
chimney defective. 

100 . In special places, such as at a door jamb, it is neces¬ 
sary to provide specially good nailing, and wood bricks are 

built into the wall as 
shown at a in Fig. 46. 
These are blocks of wood 
of the same size as a brick 
and are built in the wall 
in the same manner as 
ordinary brick. 

101 . A patented de¬ 
vice known as a wall plug 
is shown in Fig. 47. This consists of a bent corrugated piece 
of metal that is built into the joints of the brickwork and into 
which a nail can be driven securely. 

102 . Devices for attaching work to brick walls, but which 
are not built in the walls, will be discussed elsewhere, as they 
do not properly come under the subject of brickwork. 



CHIMNEYS AND FIREPLACES 


CHIMNEYS 

103 . Design. —The correct location, area, and height of 
chimneys should be carefully considered in designing a building. 
To make a chimney draw well, a separate flue should be pro¬ 
vided extending from each fireplace, stove, or furnace to the 
top of the chimney. It is not considered good practice to use 
one flue for two or more of these features, although it is some¬ 
times done with satisfactory results. 

104 . Construction of Chimneys. —Chimneys are gen¬ 
erally constructed of brick and contain fireplaces, spaces for 





u 

M'~m 

■1:: 


T c — 






Sect/or? C C. 




I L T 497 BB 246-1843-2 



Fig. 48 


97890 
















































































































































































































































































































































































































































































































































COMMON BRICKWORK 


G1 


ranges, ash-pits, flues, etc. These features are combined so as 
to form a compact and economical structure which is sometimes 
very complicated. 

An example of the arrangement of parts in a chimney is 
shown in Fig. 48, which is a chimney built in with the side 
wall of a brick building. In ( a ) is shown a front elevation of 
the chimney; in (/?), a section through the center lines of the 
fireplaces. Between these views are shown horizontal sections 
or plans of the chimney at each floor, in the cellar, and above 
the roof. 

In the upper stories are shown the fireplaces b, c, and d and 
in the basement or cellar the ash-pit a. This ash-pit receives 
the ashes from the fireplace b through the ash door shown in 
the section ( b ). The ash-pit is provided with a cast-iron door 
through which the ashes are removed. A flue e, shown in 
dotted lines in (a), reaches from the basement floor to the top 
of the chimney. At the bottom of this flue, near the floor on 
the side of the chimney, is shown an iron door for cleaning out 
this flue. At / is an opening into the flue e designed to receive 
a smoke pipe from a heater or furnace. The flue e runs up past 
the fireplaces b, c, and d and is then bent toward the center of 
the chimney. 

105 . Flues. —The flues from the fireplaces are similarly 
shown by dotted lines extending from points above the tops of 
the fireplaces to the top of the chimney. The brick partitions 
between chimney flues are called withes. As shown, the flue 
from any fireplace must pass on the side of the fireplace above, 
but the flues are deflected above the last fireplace and brought 
together so as to make the chimney, where it extends above the 
roof, as compact as possible. 

The bends in the flues should be as gradual as possible so as 
not to check the flow of smoke and gases up the flue. The 
double dotted lines indicate that the flues are lined with terra¬ 
cotta linings. These flue linings should be carefully cut to 
miter or fit together at the bends so as to form a smooth chan¬ 
nel. Flues having slight bends are considered preferable to 
perfectly straight flues, as the bends prevent rain and sleet from 

246—5 


G4 


COMMON BRICKWORK 


flue with an area of 1 X 5 X900 = 60 square inches will be 
required. According to Table II, an 8J"X13" flue must be 
used for this area. A round flue of % 8 X900 = 50 square 
inches, or 8 inches in diameter, will be needed. 

110 . Chimney Caps. —The portion of the chimney pro¬ 
jecting above the roof should be laid up in strong cement mor¬ 
tar so as to prevent its disintegration, and should be covered 
with a protecting cap of stone or concrete. This cap may be 
pierced with holes to match the flues as shown in (a) in Fig. 49, 





in which a is the capstone of the chimney and b the holes cut 
through flush with the inner edge of the flue lining and covering 
the joints between the brickwork and the linings. This pre¬ 
vents water from entering the joints of the brickwork, which 
would soon cause disintegration of the mortar, loosening of 
the bricks, and discoloration on the exterior of the chimney. 

Another method frequently followed is to project the flue 
lining above the masonry, as in (&), and to build on a concrete 
or cement cap, a. This prevents swirling air-currents, with 
perhaps accompanying snow flakes, from descending the flue. 





















































































COMMON BRICKWORK 


65 


It also tends to decrease the erosion under the cap due to 
water entering the exposed joints in the brickwork. Concrete, 
however, is more apt to deteriorate under heat, cold and mois¬ 
ture than stone, and thus is likely to prove less durable. 

A chimney cap that is not perforated is shown at a in Fig. 50. 
This cap is supported at the four corners by small brick piers 
between which the smoke passes through the spaces b. Such 
a cap prevents rain and sleet from falling into the chimney. 

111 . Chimney Pots.— Instead of flat caps, chimney 
pots made of terra cotta are sometimes used. These pots form 






a picturesque and ornamental finish to a chimney. They are 
made in many different forms, which are kept in stock by 
dealers. Examples of terra-cotta chimney pots are given in 
Figs. 51, 52, and 53 showing half exterior views and sections. 
The sections show the manner in which the pots are set, so as 
to cover the flue lining in the chimney. One pot is required for 
each flue. A strong cement mortar is used in setting the pots 
and is graded away from the pots to the outside of the chimney 
so as to form a wash. The design in Fig. 51 is a simple one 










































































CG 


COMMON BRICKWORK 


with graceful lines and is round or circular in plan. The 
design in Fig. 52 is more elaborate and is octagonal in plan. 



Fig. 52 


Fig. 53 


Fig. 53 is a larger and more elaborate design than the others, 
with outlets for the smoke in the sides as well as the top. 


FIREPLACES 

112. Construction of Fireplaces.— The general con¬ 
struction of a fireplace is shown in Fig. 54. The projection of 
the chimney into the room to enclose the fireplace is called the 
chimney breast. The height of an ordinary fireplace opening 
should be about 2 feet 6 inches or 2 feet 8 inches above the 
finished floor, its depth from 16 inches to 24 inches, and its 
width from 2 feet to 5 feet. If the height of the opening is 












































































































COMMON BRICKWORK 


67 


made more than 2 feet 8 inches the flue should be made of 
such a size that the upward draft will be strong enough to 
prevent smoke coming out into the room'. 

While a good fireplace can be made that is rectangular in 
plan, it is better to slope the sides and back as shown in the 

9 



ONE HALF ELEVATION 


SECTION d-d 


SECTION g-g 



p HAN PAT. THROAT Qc PAMPER 

Fig. 54 


figure, as these sloping surfaces throw the heat into the room. 
A slope of about 3 inches in 1 foot, as shown in the plan, is 
satisfactory. 



















































































































































































































































































G8 


COMMON BRICKWORK 


The back b of the fireplace should slope forward and form 
the throat c, which should be from 2\ inches to 4 inches in 
depth and the full width of the fireplace opening. The total 
area of the throat should be not less than the area of the flue 
lining. The throat should be, at least, 2 inches or 3 inches 
above the top of the opening of the fireplace as shown at ^ and 
as near the front of the fireplace as possible. Backs may also 
be curved, as illustrated in fireplace c in Fig. 48. 

A smoke shelf e, Fig. 54, is an important feature. It pre¬ 
vents the air from rushing down the flue when a fire is started 
and forcing smoke into the room. The smoke chamber f is 
formed by drawing the brickwork together at an angle of 60° 
on the sides until it is reduced to the dimensions of the flue 
lining. The bricks should be clipped so as to present as smooth 
a surface as possible and not a series of offsets. The lining l 
is then started, being supported by the brickwork, as shown. 
The hearth shown at j is extended in front of the fireplace so 
as to catch embers that may fall out of the fire. It is supported 
on a trimmer arch i, consisting of a single rowlock arch about 
20 inches wide springing from the chimney to the header t. 
This arch is laid upon a wooden center which is sometimes left 
in place, but is liable to be set on fire by a very hot fire on the 
hearth above. A better practice is to remove the centering of 
the trimmer arch and cover the space with metal furring and 
metal lath, to which the plastering may be applied. Upon 
the trimmer arch, the hearth is built up of cement or con¬ 
crete and is finished in tile, marble, or brick. The hearth 
should extend at least 12 inches on each side of the fireplace 
opening. In Fig. 48 is shown another design for a hearth in 
fireplaces b and c. This design is built of reinforced concrete 
which is cast partly upon wooden forms and partly upon the 
masonry of the chimney. Iron rods are placed as shown and 
the concrete is poured so as to surround them. This construc¬ 
tion forms a solid slab upon which the finish of the hearth is 
placed. This finish may consist of brick, tile, or cement. 

113. Finisli of Fireplaces.— The fireplace shown in 
Fig. 54 is lined with firebrick or good hard-burned brick. A 


COMMON BRICKWORK 


69 


loose grate in which coal may be burned is sometimes placed 
in a brick opening. In some cases ornamental sheet-iron or 
cast-iron linings are placed in the fireplace as shown in Fig. 55. 



Fig. 55 


Ill this case a hard-burned common brick or else firebrick may 
be used in constructing the fireplace, as the lining will cover 
this work. 

114. Patent Throats ancl Dampers. —As it is desir¬ 
able at times to reduce the draft in a fireplace, a damper should 
be provided that will permit of partially or entirely closing the 
throat of the fireplace. There are several patent dampers on 
the market that are designed to be built in at the top of the 























































70 


COMMON BRICKWORK 


fireplace for this purpose. An example of such a damper is 
shown in Fig. 54, which shows by solid lines the position of the 
damper when closed and the position when open by dotted lines. 
Above this damper a patent throat is sometimes used and is 
made of concrete or of terra cotta similar to the flue linings. 
This throat forms the sloping smoke chamber that would other¬ 
wise be made in brickwork. 

115. Ash Doors ancl Pits.— When possible, it is very 
desirable to have an ash door in the hearth under a grate 
through which ashes may be dropped into a suitable space in 
the cellar portion of the chimney. This arrangement is shown 
in Fig. 54, where the ash door is at p and the pit at w. A. 
door q is provided at the bottom of the ash-pit through which 
the ashes may be removed from time to time. A similar 
arrangement is illustrated in Fig. 48. 


ARCHITECTURAL TERRA COTTA 


Serial 1833 - Edition 1 

ADVANTAGES, USES, AND DESIGN 


INTRODUCTION 

1. Terra cotta such as is used for facing walls of buildings, 
forming cornices, columns, sills, and lintels over openings, etc., 
is technically known as architectural terra cotta to distinguish 
it from the form known as structural terra cotta, which is used 
in the construction of walls, partitions, floor arches, and 
enclosures for steel columns in fireproof buildings. 

2. All terra cotta is made of clay or shale, which is ground 
with water in a mill, molded into shape, and then placed in a 
kiln and burned to a brick-like consistency. Architectural terra 
cotta is made of a better grade of clay than structural terra 
cotta and is so treated as to form a plastic mass that can be 
molded into forms of very intricate pattern. Great care is 
required in forming and handling the blocks, in finishing the 
surfaces, and in burning, to secure a product that will be free 
from defects and suitable for the purpose intended. 

Although the process of manufacture has changed greatly in 
detail since terra cotta was first employed, about 600 B. C., 
the product as it comes from the kiln today is very much the 
same as that made by the ancients, who used this material for a 
variety of useful and ornamental purposes. 

3. Terra cotta is extensively used for facings for exterior 
and interior walls of buildings, and for such purposes it is % 
durable, beautiful, and economical material. 

COPYRIGHTED BY INTERNATIONAL TEXTBOOK COMPANY. ALL RIGHTS RESERVED 


1 L T 497—6 




91 


ARCHITECTURAL TERRA COTTA 


Properly made terra cotta is fire-resistant, frost-proof, and 
weather-proof, in which characteristics it is superior to stone. 
It lends itself to a great variety of color effects and can be 
molded or ornamented with comparative ease to produce either 
plain or intricately ornamented work that will stand the wear 
and tear of centuries. 

From the structural standpoint, terra cotta is a most desir¬ 
able material to use on account of its durability and adapt¬ 
ability to many kinds of structures. It is equally adaptable to 
a building having masonry walls or one having a framework of 
steel or of reinforced concrete. 


ADVANTAGES AND USES OF TERRA COTTA 

4. Facings for Walls. —Terra cotta, when used as a 
facing for masonry walls, may be bedded in mortar and built 
into the wall in the same manner as stone or brick. 

As a facing for a steel-frame or reinforced-concrete-frame 
structure, terra cotta is a desirable material, as the blocks may 
be designed and formed to fit the shape of the structural parts 
that support them. The blocks may be kept away from these 
parts a distance of from one to two inches to allow for irreg¬ 
ularities in the structure, thus avoiding expensive cutting and 
fitting such as is often required when stone is used. In the 
forms of structures mentioned the terra cotta is usually 
attached to the supports by means of metal anchors, and the 
space back of the blocks is filled with masonry except in places 
where the terra cotta fits closely to the supports, in which cases 
the space may be filled with a cement grout. 

5. An advantage that terra cotta has, when used as a facing 
for a reinforced-concrete building, is that the entire rough con¬ 
crete structure can be built and completed on the inside before 
the terra cotta is applied. The terra cotta does not require to 
be bonded with the wall, piece by piece, as the wall progresses, 
but may be put in place afterwards and secured to the wall by 
means of metal anchors that have been previously built into 



ARCHITECTURAL TERRA COTTA 


3 


the wall. By this method, the terra cotta may be in the making 
at the factory while the building is being erected. 

6. In addition to the employment of terra cotta for build¬ 
ing fronts and for interior work, there is considerable demand 
for its use in cornices and balustrades to take the place of more 
expensive cut stone, copper, or perishable sheet metal, such as 
tin or galvanized iron. 

,7. Fire-Resisting: Qualities.— Terra cotta is a good 
fire-resisting material, as it can stand the heat of a conflagration 
better than stone. It can therefore be used in office buildings 
and other structures where it is necessary to cover a steel 
frame with a material that will conceal and protect the steel 
and at the same time give a pleasing and permanent architec¬ 
tural finish to the structure. 

8. Weather-Resisting Qualities. — As a weather- 
resisting material, architectural terra cotta is very superior. 
When properly glazed it is non-absorbent and is thus excel¬ 
lent for structures built in large towns and cities where smoke 
and dust are always in the atmosphere. Terra cotta can be so 
glazed that it is impervious to water, and buildings faced with 
it can be washed down whenever desired, and made to look as 
fresh as when new. 

9. Lightness in Weight. —For special purposes where 
a saving in weight is necessary, terra cotta is especially useful, 
as in a dome where it is required that the structure shall be 
light in weight and at the same time durable and weather 
resisting. 

10. For Ornamental Work. —Terra cotta as a mate¬ 
rial for ornamental work in buildings has several advantages 
over cut stone which make it especially desirable to use under 
some circumstances. One of these is that the sculptor who 
models any ornamental part of a building in terra cotta can be 
sure that his model will be accurately reproduced, because the 
process of casting terra cotta is a mechanical one by which the 
original model made by the sculptor is exactly copied in 




4 


ARCHITECTURAL TERRA COTTA 


the plaster mold and reproduced in the clay when pressed into 
the mold. 

When stone is used, the sculptor makes a clay model from 
which a plaster cast is taken and this is copied by the stone 
carvers with more or less fidelity, according to their proficiency 
and the accuracy with which they can interpret the sculptor’s 
original model. As a rule, sculptors themselves do not carve 
the stonework but are dependent for the excellence of the 
results upon the skill of the stone cutters employed by them. 

11. Another advantage is that terra cotta can be glazed 
with any color desired, so that great variety in tint can be 
obtained; thus it is not dependent upon its natural color, like 
stonework, nor upon the color produced by the burning, as is 
the case with brickwork. The ability to glaze terra cotta with 
colors opens up a wide range of possibilities for the designer 
who appreciates the effectiveness of color in his designs. 
Color in terra cotta is not affected by time or weather. Though 
dimmed by dust or smoke, the material may be quickly restored 
to its original color by washing. Colored glazed terra cotta is 
called Faience or polychrome terra cotta, polychrome meaning 
many colored. 

White, full-glazed terra cotta, described later, is especially 
useful for the fronts of buildings, for lining light-courts, or 
wherever it is desirable to reflect the light as much as possible. 

12. Economy.—Terra cotta also has an advantage in 
economy, as it generally costs somewhat less than stone, and 
being lighter in weight requires less steel to support it. 

Terra-cotta members having richness of detail, such as flut- 
ings, ornamental panels, belt-courses, elaborately modeled 
column capitals, or similar members, can be produced in dupli¬ 
cate at much less expense than in cut stone, each unit of which 
must be laboriously carved by hand. Even in the plain mem¬ 
bers that are often used as a facing, the blocks may be formed 
of practically one size and by the use of very few molds may 
be cast in great numbers, whereas in stone facings each piece 
requires to be cut and finished as a separate unit. 


ARCHITECTURAL TERRA COTTA 


5 


DESIGN OF TERRA COTTA 

13. In designing buildings in which architectural terra 
cotta is to be used, the architect should have a good knowledge 
of the nature of terra cotta, as well as of some of the peculiar 
conditions that govern its manufacture. Architectural terra 
cotta should be designed in accordance with the characteristics 
of the material itself even when it is used to resemble some 
other material, such as cut stone. 


CHARACTERISTICS AFFECTING DESIGN 

14. The characteristics of terra cotta that affect its use 
and design are, first, that terra cotta is a burnt product that 
shrinks and warps somewhat in burning. This characteristic 
makes it difficult to use large pieces of terra cotta in plain- 
surface work, as irregularities in the surface will not look well 
in the front of a building. This defect is largely overcome by 
using the terra cotta in medium-sized blocks so that the 
deformities will be small and practically negligible. 

A second characteristic is that the clay of which the terra 
cotta is made lends itself readily to modeling or ornamentation. 
The use of modeling or ornament over the surfaces of terra¬ 
cotta work serves to conceal deficiencies due to warping and 
shrinking, and terra-cotta work containing considerable orna¬ 
mentation always looks better than plain work. This modeling 
can be done quite easily and, after a mold has been made for 
a piece of ornament, a great number of similar pieces can be 
cast in the same mold. Hence, the oftener an ornament is 
repeated on a surface the less will be the cost of the terra 
cotta per piece, as the repetition of the same pattern will be 
much cheaper than the use of a number of different patterns. 

A third characteristic is that very elaborate, bold, and pro¬ 
jecting ornament for special positions can be easily made in 
terra cotta. The modeler makes the desired form in clay and 
the model is cut up into suitable-sized pieces, dried, glazed, and 
baked 



6 


ARCHITECTURAL TERRA COTTA 


A fourth characteristic of terra cotta is that it can be colored 
in any desired tints and thus a field for design in color is 
opened to the designer. 

A fifth feature is that it can be finished so as to resemble 
other materials, especially cut stone. 

Thus terra cotta lends itself readily to ornamental treatment 
either of a bold or a delicate nature, to elaborate or delicate 
color effects, and to texture design. 


PLAIN SI RFACES 

15. Plain Blocks. —Where plain blocks are used to 
obtain certain features, such as ashlar faces, plain piers, 
mullions and panels, they should be medium in size and care¬ 
fully finished before drying, and the joints should be rubbed 
so that the two adjoining blocks will fit together with per¬ 
fect accuracy. A wall composed of plain blocks that are even 
slightly warped will have an uneven appearance, but if the 
blocks are paneled, molded, or ornamented in any way that 
tends to make the wall irregular in appearance, the eye will not 
notice any slight warping that may exist. 

The effect of the shrinking and warping in plain blocks of 
terra cotta, due to the heat of baking, is shown in the flat por¬ 
tion of the wall above the second-story windows in Fig. 1. 
If, however, this part of the fagade had been built with blocks 
about 10 in.X16 in. or 12 in.X20 in. in size, as has been done 
in the panel between the first- and second-story windows, these 
blocks could have been made so that the slight irregularities of 
the surfaces and joints would not be apparent. In contrast 
with this example is the wall similarly treated in Fig. 2, in 
which the blocks are made small and the imperfections are thus 
reduced to a negligible quantity. In addition to making the 
blocks small, the edges of the blocks are beveled. This treat¬ 
ment also tends to conceal any imperfections in the joints due 
to warping. This style of design is not recommended for large 
surfaces as it is adaptable only for designs using a tile or 
diaper effect. 

Fig. 3 shows a building with a terra-cotta fagade having 




246—6 























8 








































































9 




























10 


ARCHITECTURAL TERRA COTTA 


plain stone-like surfaces which, while excellent, show slight 
irregularities in this case although they are excellent for 
terra-cotta work. 


MODELING TERRA COTTA 

1G. Fig. 2 not only shows a proper treatment of terra cotta 
in plain blocks but illustrates the superior appearance of the 
terra cotta when richly decorated. It will be noted that there 
is a considerable repetition of blocks of the same pattern, which 
would be extremely costly if worked in stone. This example 
illustrates the possibilities of ornamentation in terra-cotta work 
in several ways. Shallow modeling, or lozv relief work, is 
shown in the borders and band courses. Bold modeling, or 
high relief, is illustrated in the wreaths around the circular 
windows and in the capitals of the polygonal piers. An excel¬ 
lent illustration of figure modeling is shown in the panel of 
dancing figures above the main entrance. This building is a 
very good example of the intelligent use of terra cotta. 

17. Repetition of Ornament. —It is economical in the 
use of any plastic material, such as clay, to use the same orna¬ 
ment or motif repeatedly in the design, as this tends not only 
toward harmony of design, which might be too complicated 
otherwise, but also toward economy in manufacture. As every 
piece of terra cotta employed in a building must be formed in a 
mold, the fewer molds that are required the less will be the 
cost of the work. As the number of pieces needed in even a 
small structure often runs into the hundreds, and on larger 
buildings into the thousands, it can be readily seen that a large 
number of molds greatly increases the expense of manufacture. 
By repeating patterns, the same plaster mold can be used to cast 
from 25 to 40 blocks of the same design, which greatly reduces 
the cost of manufacture. 

Designers should, therefore, see to it that they make their 
designs economical by using a repetition of patterns as much as 
possible. Thus, a simple running cornice in which each block 
is like its neighbor on either side, is less expensive to produce 
than a cornice composed of blocks of several different patterns. 




11 
































Fig. 5 


12 






















































ARCHITECTURAL TERRA COTTA 


13 


Lintels and sills for windows, if all of the same pattern, can 
be produced with a minimum number of molds, but if the lintels 
on each story vary, or if the several parts of each lintel are 
different, the number of molds required will be very large. 

18. Modeling: in High Relief.— Terra cotta can be 
modeled in high relief ; that is, the ornament can be made so as 
to project boldly, as illustrated in Fig. 1, where an eagle in high 
relief is shown in the panel at the middle of the building above 
the windows. Bold modeling is also shown in the caps of the 
terra-cotta piers in Fig. 4, as well as in the ornament over the 
cornice of the door in Fig. 5. In fact, any projection that can 
be carved in stone can practically be made in terra cotta. 

19. Limitations in Size of Blocks.— Stone can be used 
in large units, its size being determined only by the practicable 
size in which it can be quarried, worked in machines, shipped, 
and erected in place. Thus even huge columns of stone may 
be monolithic, or of a single piece of stone. Terra cotta, how¬ 
ever, cannot economically be molded in very large units. There 
are several reasons for this. When undergoing the drying 
operation in the dry room, shrinkage in large pieces would be 
so much more than it is in small units that the blocks would 
tend to warp and crack. After drying, uniform burning in the 
kilns becomes very much more difficult with large blocks than 
with small ones and the warping is greatly increased because 
the heat does not attack all surfaces evenly. The handling and 
shipping of large blocks requires much more care than when 
smaller units are employed and there is much more waste from 
broken blocks. Hence the cost is greatly increased. It is not 
economical to use blocks greater in size than 27 in.X24 in. 
X36 in. Blocks, especially thin facing or veneering blocks, are 
made much smaller than this size, as the smaller blocks are 
usually more economical to manufacture. 

20. Practical Sizes of Blocks.— As a guide to the archi¬ 
tect when designing terra-cotta work, Table I is given to show 
the most practical sizes of blocks to use for some of the prin¬ 
cipal parts of a building. In the table, the dimensions given in 


14 


ARCHITECTURAL TERRA COTTA 


the column headed Depth into Wall include not only the depth 
that the block extends into the wall but the amount it projects 
beyond the face of the wall. Thus, a cornice that extends 
10 inches from the wall should extend about the same distance 


TABLE I 

PRACTICAL SIZES FOR TERRA-COTTA BLOCKS 


Members 

Height 

Inches 

Width 

Inches 

Depth into Wall 
Inches 

Cornices and string-courses. 

10 to 24 

18 to 24 

12 to 24 

Walls or panels. 

4 to 24 

12 to 24 

4 to 18 

Sills and lintels. 

4 to 12 

14 to 24 

4 to 20 

Jambs . 

14 to 24 

4 to 12 

4 to 12 

Column drums. 

10 to 16 


10 to 20 in Diameter 

Columns, Segmental. 

10 to 16 


10 to 24 Radius 


into the wall, and its Depth into Wall dimension would be 
20 inches. This applies generally, except when the terra cotta 
is supported by steel work attached to the frame of a building, 
when the blocks may extend only 4 inches into the wall. 


COLORING TERRA COTTA 

21. Some of the most interesting designs in modern terra 
cotta are in colors, such as blues, greens, yellows, browns, and 
reds. Polychrome terra cotta in such designs is largely used 
for churches, office buildings, store fronts, theaters, and interior 
decorations; in fact, wherever the design itself is susceptible to 
the proper use of color. Usually the background of terra cotta 
is kept in one tone and the modeled portions of the design are in 
variegated colors. Hence, the latter stand out from the back¬ 
ground, and many rich and beautiful effects are obtained. 

In Fig. 6 is shown a good example of the use of polychrome 
terra cotta. In this case it is used for a theater front. The one- 
tone background consists of plain-surfaced pieces in a cream 
color and the modeled portions are in blue, green, and brown. 
The large panel immediately over the entrance to the building 


































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I T. T 497—1833 






























































































































































































15 


ARCHITECTURAL TERRA COTTA 

is also formed of plain pieces, in a gray color. This panel is 
intended for an advertising sign which may be applied to its 
surface. 


DESIGNING TO RESEMBLE OTHER MATERIALS 

22. Architectural terra cotta is frequently designed to 
resemble other materials, such as stones of different kinds, and 
with various finishes. Granite, with its mottled or speckled 
coloring, limestone and sandstone with the various toolings of 
the surfaces, can be closely copied. The cost of the terra 
cotta is generally less than the cost of the stone. Terra cotta is 
frequently used in conjunction with stone on the same building, 
the walls and plain surfaces being finished in the stone, and the 
ornamental parts, such as cornices and the more richly deco¬ 
rated portions, being formed of terra cotta. When new, the 
difference in the materials can hardly be distinguished, but 
after a time the effect of the weather often causes a decided 
difference in the appearance. In using terra cotta to resemble 
another material the designer should never lose sight of the 
limitations of terra cotta. 

23. Terra cotta that is designed to resemble some other 
material, such as granite or Bedford limestone, should have 
the forms of the blocks and the joints as like as possible to 
those generally employed for the material it is to be like, other¬ 
wise the effect it is desired to obtain may be lost. 

To follow out this idea, quoins and rustications are some¬ 
times used, arches with keystones may be employed over open¬ 
ings, and often pilasters and panels are used. In a fagade 
intended to resemble cut stonework the greater number of 
vertical joints required by terra cotta, because of the small 
size of the blocks, tends to spoil the effect, but a little careful 
planning will make it possible to put many of the vertical 
joints in angles where they will not be noticeable. 

24. In Fig. 5 is shown a building entrance made of terra 
cotta formed to resemble granite. This entrance is designed 
with both plain and ornamented parts. The lower members 
adjoining the doorway, which in the illustration show darker 



1G 


ARCHITECTURAL TERRA COTTA 


than the remaining portions, are finished with a glossy surface 
called full glaze and the other portions are finished with a less 
glossy surface called mat glaze. These terms are defined more 
fully later in this Section. It will be noted in this illustration 
that the blocks of the upper part of the doorway are small in 
size, as indicated by the numerous joints, while no joints are 
visible in the lower members. This is due to the lower mem¬ 
bers being made in long narrow pieces and the joints being 
formed vertically in the design, where they are not noticeable. 
This gives this lower part the appearance of being formed of 
large pieces of granite, which adds very much to the attractive¬ 
ness of the design. 

25. In Fig. 3 is shown a building which has the entire 

front faced with terra cotta designed to obtain the efifect of 

$ 

light-colored stone or white marble. The panel above the cor¬ 
nice, which forms the background for the balusters, is formed 
of small pieces. By locating the joints behind the balusters, 
the sizes of the blocks are not apparent, and the efifect produced 
is that of the panel being formed of one large slab. 

The columns of this building are formed of small pieces. If 
they were to be of stone, they would either be in large pieces 
or in a single piece for the entire shaft of the column. The 
entire front is formed of pieces of terra cotta that are, as nearly 
as possible, of the sizes and form that would be used were the 
material stone, thus carrying out the principle stated in 
Art. 23. 


20. Figs. 7, 8, and 9 all show the use of terra cotta in the 
construction and decoration of buildings of dififerent types. 
In Fig. 7 is shown a handsome country residence in which 
terra cotta is used in place of stone for all the trimmings. The 
terra cotta is treated in a more ornamental manner than stone 
would be. The similarity of design in many of the parts is 
evident in the panels under the windows, over the entrance 
projection and over the porch. The square panels above the 
windows over the porch and over the entrance are of two pat¬ 
terns and are cast from two molds. The short pilasters around 
the top of the wall above the porch and the entrance are all of 





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I L T 497—7 













Fig. 8 


18 










































ARCHITECTURAL TERRA COTTA 


19 


the same pattern and made with one mold. Thus a very elabo- 
late ornamentation is obtained by the use of three molds from 
which a great number of similar pieces have been made. 



Fig. 9 


27. An apartment building is shown in Fig. 8 which illus¬ 
trates a profuse ornamentation made of terra cotta. The 






























































































































20 


ARCHITECTURAL TERRA COTTA 


basement walls are of plain terra cotta resembling stone, 
while the trimmings of the doors and windows are of molded 
and ornamented terra cotta used in the same manner as stone is 
used. The profuseness of the ornament is characteristic of 
terra cotta. 

28. The building shown in Fig. 9 has the first-story walls 
faced with terra cotta designed like rusticated stonework. 
The balcony at the second-floor level has the design formed 
with plain blocks, and the brackets that support the balcony 
are very ornamental. The cornice and the members that sur¬ 
round the windows of the upper stories are all of a design 
that would be consistent were stone used for this purpose. 

29. In all of these figures is shown the repeated use of 
similarly formed blocks both for plain and ornamented parts. 
Were the material stone, the ornamental parts of the design in 
many cases would not be attainable on account of the excessive 
cost in executing the designs in this material. 


STOCK DESIGNS 

30. Most of the terra cotta used for buildings is especially 
designed by the architect and is made to order. As the process 
of manufacture requires from six to eight weeks after the 
approval of the drawings and details, the architect often finds it 
desirable to use stock designs that can be obtained quickly and 
which often suffice for small structures. Most manufacturers 
keep a stock of molds for certain designs. The use of these 
stock molds reduces the cost of manufacture materially and 
also shortens the time required to make the terra cotta. 

The designs that the manufacturers keep in stock neces¬ 
sarily consist of the more ordinary forms, for no manufacturer 
could afford to manufacture and carry a very extensive variety 
of patterns not knowing what the market demand might be. 

For use in brick buildings, manufacturers also carry a line 
of stock designs for terra-cotta inserts, such as small orna¬ 
mental blocks and small panels that can be readily inserted in 
face brickwork to produce an ornamental design. 



ARCHITECTURAL TERRA COTTA 


21 


Architects who contemplate using stock designs of terra 
cotta can obtain catalogs from manufacturers showing what 
patterns they carry in stock and giving the colors, finishes, and 
dimensions. The building in which it is proposed to use such 
patterns must, of course, be designed to fit the stock form of 
blocks, for the blocks cannot be cut and must be used in the 
size and shape in which they are manufactured. 

An illustration of the use of stock patterns of terra cotta for 
a building front is shown in Fig. 1. The members which form 
each ornamental band or belt-course, also the panels of the 
pilasters, are small units of the same design, and plain pieces 
of terra cotta are used in various sizes to secure the required 
spaces for the ornamental parts. The coping is formed of both 
plain and ornamented pieces and is raised at intervals by means 
of special pieces to suit the requirements of the large ornaments 
that are placed over the second-story windows. 

The panels over the first-story entrances, which contain the 
lettering, require to be made to order. 


STRENGTH AND W EIGHT OF TERRA COTTA 

31. Well-burned terra cotta will stand a compression test 
of 5,000 pounds per square inch, which is ample for any loads 
that are likely to be placed upon it. 

The weight of hollow terra-cotta blocks, unfilled, is from 
65 to 85 pounds per cubic foot. When filled with brick they 
weigh from 120 to 130 pounds per cubic foot, and when filled 
with concrete, from 130 to 140 pounds. 


ARCHITECT’S DRAWINGS 

32. The architect’s drawings are made to show the design 
of the building which the architect has conceived and which he 
wishes to erect. They also are made to express the require¬ 
ments of the design in such a manner that the contractor and 
the workmen may comprehend the intentions of the architect, 
provide the necessary materials and labor, and erect a struc¬ 
ture of the form and design required. 






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ARCHITECTURAL TERRA COTTA 


23 


The architect’s original working drawings usually consist of 
plans, elevations, and sections, drawn to a scale of \ inch or 
i inch to the foot. These should clearly indicate the various 
materials that are to be used and the general form of con¬ 
struction. If terra cotta is to be used, the drawings should 
show the parts that are intended to be plain, those that are to 
be ornamented, and the general supports on which the terra 
cotta is to rest. These drawings will be sufficient for the 
manufacturer to bid from. 

After the contract for the terra cotta has been awarded, the 
architect should prepare large-scale drawings that will show 
fully the forms of the terra-cotta parts and will give sugges¬ 
tions as to the jointing. He may if he desires prepare full- 
size details that will show the contour of all moldings, as well 
as the nature of the ornamental parts. These drawings are 
then given to the manufacturer to follow when making his 
shop drawings. It is customary, however, for the architect to 
require the terra cotta manufacturer to make the full sizes in 
which case they are drawn to shrinkage scale. 

33. Example of an Architect’s Drawing'. — An 
example of an architect’s drawing for an entrance and wall 
finished in terra cotta is shown in Fig. 10. Such a drawing is 
generally made to a scale of | inch=l foot. An elevation of 
part of the entrance is shown in ( a ) and a section through the 
entrance in (b). At a in (a) are shown the architect’s sug¬ 
gestions for the horizontal jointing of the wall blocks; at b, 
the jointing for the arch over the entrance; and at c, the joint¬ 
ing for the terra cotta in the wall where it intersects with the 
arch. The jointing of the ornamental panel over the entrance 
is not shown in this drawing, as it is left to the manufacturer to 
determine what forms of blocks he can cast that will conceal 
the joints as much as possible. 


246—7 


24 


ARCHITECTURAL TERRA COTTA 


MANUFACTURER’S DRAWINGS 

34. The architect’s drawings are sent to the manufacturer 
of the terra cotta, who copies them and adds details of jointing 
and of anchoring the blocks to the constructional parts of the 
building. These drawings are then submitted to the architect 
for approval. The architect makes any changes and corrections 
on them that his judgment may dictate, marks them Approved, 
and returns them to the manufacturer. The manufacturer 
then proceeds to make further detail drawings which are 
drawn to what is called the shrinkage scale as will be described 
presently. 

35. Example of a Manufacturer’s Drawing.— In 

Fig. 11 is shown the manufacturer’s drawing of the same 
entrance that was shown in Fig. 10. It will be noted that the 
horizontal joints of the plain wall, the radiating joints of the 
arch, and the joints c between the wall and the arch, as shown 
in Fig. 10 (a), have been retained. Vertical joints d, 
Fig. 11 (a), however, have been added to show the length of 
the wall blocks. The joints e and / are suggested for the orna¬ 
ment over the entrance. These joints are made to follow the 
form of the ornament as far as possible so that they may be 
partly concealed. 

In Fig. 11 (b) is shown the contour of the terra-cotta blocks 
that occur in this section, the depths that these blocks set into 
the wall, and the manner in which they are secured or sup¬ 
ported. All of the terra cotta over the doorway, also the 
masonry with which it is backed up, is supported by the steel 
members shown at a and b. Anchors c are used to tie the pro¬ 
jecting blocks to the body of the wall. The blocks d are 
designed to form a self-sustaining arch, as shown at g in (a). 
To prevent any settlement of these blocks or the opening of the 
joints between them, they are usually anchored to the steel 
members by means of small suspension rods, shown at / in ( b ). 
The blocks e in ( b ) are likewise suspended from the steel 
member a. The diagonal lines show the backing which consists 
of brickwork. 


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25 


























































































































































































































26 


ARCHITECTURAL TERRA COTTA 


In addition to the general dimensions, the manufacturer’s 
drawings usually indicate the sizes of the blocks, as in Fig. 11. 
When these scale drawings have been approved by the architect, 
the manufacturer proceeds to lay out the details of the various 
blocks at the shrinkage scale, which is a scale that makes 
allowance for the shrinkage that invariably occurs when 
burning the blocks. 



36. Shrinkage of Terra Cotta. —Since terra cotta 
shrinks in manufacture about 1 inch per foot, the full-size 
shop drawings are drawn larger than the required size of the 
completed blocks. Thus, when it is desired to make a block 

12 inches long, the shop 
drawings show it 13 inches 
long. The plaster model 
and resulting plaster cast 
will be 13 instead of 

12 inches long and the 
pressed-clay block will be 

13 instead of 12 inches 
long. After the block has 
been dried and burned, 
however, it will be found 
to have shrunk to about 
12 inches, or the size re¬ 
quired. 

Shrinkage can be esti¬ 
mated quite accurately, 
but it sometimes varies as 
much as £ to £ inch per 
foot. Thus, a block estimated to shrink to an even 12 inches 
might prove to be when burned, £ to £ of an inch longer or 
shorter when it comes from the kiln. For this reason terra¬ 
cotta blocks are cast with a lug at each edge, which can be cut 
or rubbed down by machinery to make the block the exact size 
required. 

The form of lug that is usually cast on the upper and the 
lower edges of the blocks is shown at a in Fig. 12. At the 



































ARCHITECTURAL TERRA COTTA 


27 


ends of the blocks a similar form of lug is cast, as shown at b, 
and this projects beyond the face of the shell of the block c. 

Variation in shrinkage is affected by the moisture or the 
stiffness of the clay when pressed into the mold, and by the 
dryness of the plaster mold in which the clay is pressed, since 
a dry mold will absorb more moisture from the clay than a 
moist mold. It is also modified by the exactness with which 
the clay ingredients are mixed, by the atmospheric conditions 
while the block is drying, and by the varying degrees of heat in 
different parts of the same kiln. 

37. Design of Steel Supports, Anchors, Etc. —All 

the loose steel and iron necessary to attach, or anchor, the terra 
cotta to the building proper, must be designed by the terra¬ 
cotta manufacturer and shown on the drawings. He should 
also provide a schedule, or list, of all this iron and steel with his 
final drawings. Sometimes the contract requires that the terra¬ 
cotta manufacturer provide all this steel work, but as a rule the 
steel contractor provides it according to the schedule and draw¬ 
ings prepared by the terra-cotta manufacturer. 

38. Final Approval of Manufacturer’s Drawings. 

When the manufacturer’s shop drawings are completed, they 
should be carefully reviewed by the architect to see that the 
designs conform in every way with his details from which the 
shop drawings were made. These shop drawings should show 
the full sizes of all moldings, the general construction of the 
terra cotta, and the proposed methods of anchoring the blocks 
to the building. The jointing also should be indicated. 

It may be necessary for the shop drawings to be changed a 
number of times before they meet with the approval of the 
architect in all particulars. He should carefully review the 
final drawings and approve them before they are handed back 
to the manufacturers. 


28 


ARCHITECTURAL TERRA COTTA 


MODELING 

39. When the architect has approved the drawings and has 
marked them accordingly, the work of modeling the various 
blocks is then begun. The plain work in which no molding or 
ornament appears is given to the average workman. Those 
parts of the work that consist of ornamented moldings, panels, 
cornices, brackets, and sculptural details are given to modelers 
of ability, whose duty it is to interpret the drawings in an 
artistic manner. Large manufacturers of terra cotta appreci¬ 
ate the importance of good models and usually employ only 
the most skilful men for this branch of the work. The results 
are that terra-cotta work can be used where fine artistic work 
is required and that this material is not considered as a mere 
substitute for stone, but as a material capable of the finest 
artistic expression when used in accordance with its peculiar 
characteristics. 

40. Models. —Models are made for all ornamental pieces 
of terra cotta. These models are made of plaster of Paris, 
which forms the background, and moldings and the ornament 
are modeled in clay on the plaster backing. They are always 
made according to the shrinkage scale, that is, each 13 inches 
represents 12 inches in the finished product. The models of 
large pieces of ornament, panels, etc. are made without joints. 
The joints are put in later after the model has been finished 
and is ready to be cut up into blocks of convenient size. 

41. Inspection by the Architect.—When the models 
are completed according to the drawings, the architect is noti¬ 
fied; and if it is not convenient for him to call at the works 
and inspect the models, photographs are taken, a rule being laid 
alongside of each model to show the size and scale, and these 
photographs sent to the architect for inspection and approval. 
When this method is followed, two copies of the photograph 
of each model are usually sent to the architect, who indicates 
the suggested corrections and changes on each copy, returning 
one copy to the manufacturer and retaining the other copy for 


ARCHITECTURAL TERRA COTTA 


29 


the purpose of comparison with a later photograph which is 
sent him after his suggestions have been incorporated in the 
model. If the later photograph indicates that the model is 
satisfactory, he notifies the manufacturer accordingly. 

If the architect can visit the plant to inspect the models for 
the terra cotta, it will prove more satisfactory than to attempt 
to judge and approve the models from photographs, as he can 
better appreciate the form, size, and details of his design by 
seeing them executed at full size in clay. He can also suggest 
changes that he may wish to make and have these incorporated 
in the clay and thus secure the desired effect. This done, he 
can approve the model and work can progress without further 
delay. 

42. Cutting- Up the Model. —After the model has been 
approved, it is cut into pieces of the right size from which to 
make the molds. The manufacturer usually determines the 
form and size of blocks that he considers best adapted to the 
design and to secure the best results in the burning.' The joint¬ 
ing is indicated on the model or on the photograph that is sub¬ 
mitted to the architect for his approval. Thus, an ornamental 
panel that may be 8 or 10 feet in diameter and in a single piece 
when inspected by the architect, might afterwards be cut into 
pieces not greater than 18 by 24 inches in size. The finished 
terra cotta comprising this panel will be cast in small blocks 
and combined to form the completed panel, all joints being 
filled with mortar. 

If the joints are to be inconspicuous, the fact should be made 
known to the manufacturer before the model is cut into pieces, 
so that the joints may be cut around the ornaments, or that 
other steps may be taken to prevent the joints from showing 
when the different panels are built up. 


30 


ARCHITECTURAL TERRA COTTA 


MOLDS 

43. Plaster Molds. —To reproduce in terra cotta the 
design that has been formed in the model, it is necessary to 
make a plaster-of-Paris mold of the model and use it as a 
mold into which the plastic clay is placed. 

The plaster-of-Paris mold requires to be strongly constructed 
to withstand the pressure of the moist clay. It is usually rein¬ 
forced with J-inch square steel rods and the sides are bound 
with steel strap irons. 

After the clay block has been formed, it is allowed to remain 
in the mold a sufficient length of time to dry properly before 
being removed. When it is removed it has the same contour 
and ornament as the original clay or plaster model. 


MANUFACTURE OF TERRA COTTA 


MATERIALS 

44. Architectural terra cotta is made in somewhat the 
same manner as hollow tile or brick; that is, it is a material 
molded in clay and afterwards burned in a kiln. The manu¬ 
facture of architectural terra cotta, however, requires a much 
more refined process than the manufacture of brick or hollow 
tile, the method is also more complicated, and the product must 
be worked with a larger amount of skilled labor. 

45. Clay. —Clay used for architectural terra cotta must 
be of a higher grade than that used for brick. Terra cotta that 
is to be glazed requires clay free from impurities that tend to 
fuse in the kiln, as this action will cause the glaze to pop, 
making unsightly stains, crazing, or fractures. 

46. Shale. —Shale is very largely used for the manufac¬ 
ture of terra cotta. Clay and shale from different parts of the 
country acquire different colors when burnt in the kiln, some 
coming out with a light yellowish tint, some a deeper shade of 




ARCHITECTURAL TERRA COTTA 


31 


salmon, others light or dark buff, while some are a strong brick 
red. 

As terra cotta is a material that may be artificially glazed, the 
finished color does not depend upon the natural color of the 
body that is secured by the burning. 

47. Location of Plant.— A plant for the manufacture 
of terra cotta is rarely located close to the source of supply of 
the required clay, for usually it is more desirable to keep the 
factory near the supply of labor and ship the clay such dis¬ 
tance as is necessary. Furthermore, the bank of clay some¬ 
times runs out, or the clay changes in charactei to such an 
extent that it is not suitable for the quality of terra cotta 
desired. 

48. Treatment of the Clay.— The clay is received at 
the factory and is allowed to weather, which causes it to 
crumble and pulverize. It is then mixed with about 30 per 
cent, of burned clay that has been ground fine. The mixture is 
then pulverized by special machinery, and afterwards mixed 
with water and treated in a pug mill until it becomes a smooth 
soft mass of material capable of being molded or cast. It can 
be kept in that state until required for use. 

49. Manufacture of Blocks.— The prepared clay is 
taken to the pressing room, where it is pressed into the plaster- 
of-Paris molds and then artificially dried with hot air, a process 
that usually requires from 2 to 3 hours. By this time the mate¬ 
rial has dried and stiffened sufficiently so that the blocks can 
be taken from the molds and handled without injury. 

The raw blocks are then finished; that is, the seams are 
removed and the ornament is cleaned out. 

If the blocks are to be finished with a smooth glazed surface, 
they are troweled smooth, and in this process the pores of the 
clay become closed and the finished surfaces of the material 
are made smooth and firm to receive the glaze. 

Next, the blocks are placed in dryers, where they are sub¬ 
jected to hot air. This expels all moisture from the blocks, 
gradually making them bone dry. This drying takes about 
48 hours. 


32 


ARCHITECTURAL TERRA COTTA 


The blocks then go to the glazers, where the exterior, or 
visible, surfaces are coated with a color or glaze as desired. 
They are then ready for burning and are taken to the kiln and 
subjected to a heat of from 2,000 to 2,300 degrees F. The 
burning process usually lasts from 12 to 14 days. 

All terra-cotta blocks are made hollow, and the outside shell, 
which is usually 1 inch thick, is stiffened with webs, which are 
also about 1 inch thick. The number, size, and thickness of 
the webs and the thickness of the shell are determined by the 
size of the blocks, large blocks requiring a thicker shell and 
more webs than small ones. The voids are placed about 
6 inches on centers. 

Webs and shells of blocks have holes cast in them to facili¬ 
tate anchoring them to the wall or structure. These holes also 
facilitate the handling of the blocks, as it is possible to pass 
the fingers through the holes when carrying the blocks. At 
the same time holes make the blocks lighter in weight and fur¬ 
nish a better bond for the mortar, which can flow into them 
and form a key. 


FINISHES AND COLORS 

50. Owing to the fact that terra cotta is formed of plastic 
clay, any finish or texture of the surface may be obtained by 
treating the block when it is being formed. Like pottery and 
faience, the clay may also be tinted, and any color, combination 
or blend of colors may be secured when it is burned in a kiln. 

51. Texture. —The texture of the material is obtained in 
three ways: (1) By reproducing the sample of the surface to 
be matched, by modeling it in clay in the face of the plaster 
model before it is molded. This method is used to reproduce 
picked, stippled, crandaled and bush-hammered surfaces; 

(2) tooled surfaces are cut in the mold by special tools; 

(3) smooth-, light-, and rough-drag surfaces are obtained with 
finishing tools after the blocks have been removed from the 
mold. These textures may imitate rough, smooth, tooled, or 
polished stonework. To produce imitation granite, limestone, 
or sandstone, the manufacturer uses for his model a block of 



ARCHITECTURAL TERRA COTTA 


33 


real stone and can produce an accurate imitation, either of 
polished or dull finish or of the texture given to the stone by 
means of tools or hand modeling. 

52. Coating or Spotting of Terra Cotta. —In terra 
cotta the original mixture of clay has little influence on the 
final color, which is obtained by tints applied in the form of 
slips, or glazes. These glazes produce the plain colors such as 
are seen in polychrome terra cotta. The mottled finishes are 
obtained by spotting the surface or the slip with various colors 
to produce effects such as the mottled colors of granite or 
other stones of a spotted nature. Thus, by combining spotting 
and texture, endless variations are possible. 

53. Glazing.— The final process of treating terra cotta 
before it is burned is known as slipping or spraying. 

Terra-cotta plants usually maintain a laboratory where the 
various clays, colors, and glazes are experimented with. 

- Mineral colors are used in coloring and glazing and these mate¬ 
rials do not look the same after they are baked as when they 
are applied to the unburned block. The burning produces a 
chemical change in the colors. Hence when seeking new shades 
of color the chemist applies the coloring material to a small 
briquette of terra cotta, burns it, and notes the results. The 
formulas for all mixtures of color and glaze are carefully pre¬ 
served, so that given colors can be reproduced at any time. 
When it is decided to use a certain color or glaze, the coloring 
materials are carefully weighed and mixed together in exact 
proportions with the greatest care according to the formula for 
that color. The colors are mixed with water and applied to 
the blocks before burning, by means of a spray from an air 
brush. With some glazes or where a full gloss is desired on 
the surface, it is sometimes necessary to put on an under glaze 
as a first coat, and apply the final glaze over this. 

54. These glazes are used to furnish the colors required 
by the design and at the same time they make the surface of 
the terra cotta more or less impervious to water. There are 
four finishes that are usually specified by architects. These are 


I L T 497—8 


ARCHITECTURAL TERRA COTTA 


o < 

D 1 * 

the standard, or unglazed, which is not wholly impervious to 
moisture; the vitreous, which is impervious to moisture; the 
mat-glazed, or mat-enameled, which is glazed, has a dull finish, 
and is impervious; and full-glazed, or enameled, which is 
impervious and has a glossy finish. 

In addition to these standard finishes, terra cotta, as has 
been stated, can be treated in any desired shade or color, to 
form polychrome terra cotta. Different parts of the block may 
be treated with different colors. If not otherwise specified, 
most manufacturers base their estimates on the standard color, 
which is that of light Indiana limestone, and is unglazed. 

55. In standard finish, the terra-cotta blocks, after drying 
and before burning, are covered with a coating of clay slip, 
applied with an air brush. This produces a dull‘finish which is 
not “glassy” and the terra cotta so treated is not impervious to 
moisture, but has about the texture of good hard burned face 
brick. 

In the vitreous finish, the glaze, or slip, is prepared with 
more of a glass-like quality by the addition of suitable minerals. 
This is also put on with an air brush, and two coats may be 
necessary to obtain the color desired, the first coat being a slip 
of one color to fill the pores of the blocks and the second coat 
a glaze of the same or another tint, depending upon the effect 
desired. 

The glaze used in the vitreous finish vitrifies when burned; 
consequently, terra cotta with this finish is impervious to mois¬ 
ture. This glaze is, however, very thin. 

Mat-glazed, or mat-enameled, finish, as its name sug¬ 
gests, is a dull glazed finish in which the glaze employed is of a 
glass-like nature but the finished blocks are not glossy. The 
glaze is heavier than that used on semiglazed terra cotta. The 
surface of mat-glazed terra-cotta blocks is impervious, hence 
they are excellent for outside work where the weathering 
qualities of the blocks must be considered. Mat-glazed finish 
can be washed down as readily as full-glazed. 

Full-glazed terra-cotta blocks, as their name implies, are 
coated with what is practically liquid glass, which when burn- 


ARCHITECTURAL TERRA COTTA 


35 


ing fuses and leaves a glossy finish excellent for its weathering 
qualities and because it can so readily be washed clean. This 
finish is, however, expensive and not frequently used. 


FITTING AND NUMBERING THE BLOCKS 

56. Fitting’ the Blocks.— After the terra-cotta blocks 
have been burned they are allowed to remain in the kiln until 
they cool. They are then taken to the storage shed and the 
pieces are laid out on a floor in the order in which they will 
appear in the finished building. The pieces are carefully fitted 
together to see that they are the exact size and shape called for 
by the shop drawings. Any pieces that are imperfect are 
sorted out and new pieces made to take their places. 

When the blocks are laid out, every block in a string-course 
or cornice, lintel, or jamb is carefully placed to see that the 
length of the course is just right as shown on the plans. Thus, 
a cornice composed of many blocks of terra cotta is like one 
composed of cut stone, each piece of which must be carefully 
made from the architect’s drawings so that when they are 
placed together and the proper allowance made for the mortar 
joints, the total length will meet the requirements of the 
drawings. 

Some of the blocks may require to be cut down slightly, and 
to accomplish this result the lugs on either end, which are 
provided for this purpose, are cut with a chisel; or if the excess 
is very slight, as is usually the case, one or both ends of the 
blocks are rubbed down by machinery. 

It is the usual practice to rub or cut down all adjoining edges 
of blocks whether any great excess of length has to be removed 
or not, as this treatment secures a true and square edge at the 
joints, consequently the lugs are formed sufficiently long to 
permit of this rubbing without cutting into the shell of the 
block. 

To insure the proper inspection and jointing of the blocks 
by the manufacturer at the plant, however, the architect should 
incorporate in his specifications definite requirements regarding 
this work. This is desirable in order that imperfect pieces may 




Fig. 13 


36 































































































































































































































ARCHITECTURAL TERRA COTTA 


37 


be replaced as soon as possible instead of waiting for errors to 
be discovered at the building, when the work will be delayed 
while new pieces are being made. 

57. Numbering' the Blocks.—After the blocks have 
been fitted together at the factory, each piece is marked on 
the back with black paint. A diagram is then made which 
shows each block of terra cotta, and this is marked with letters 
and numbers to correspond with those placed on the blocks. 
This diagram is sent with the shipment of terra cotta to the 
building so that the workmen can readily assemble the blocks 
in precisely the same order in which they were fitted at the 
factory. 

This assembling diagram, sometimes called the setting plan, 
usually consists of a blueprint of the manufacturer’s scale 
drawing on which is shown every block and all the joints. 
Fig. 13 is an illustration of such a plan for the terra-cotta 
entrance shown in Fig. 11. The terra cotta of each story is 
usually indicated by a large capital letter, A representing the 
first story and B the second story, etc. Each special feature 
is represented by a smaller capital letter, that, in connection 
with the larger capital letter and a number, is used in marking 
each block. 

Thus, the plain wall facing for the first-story wall is 
labeled A, as indicated in Fig. 13, and each block has a special 
number. The arch over the entrance is marked A D . All the 
pieces of terra cotta forming this arch are marked A D and a 
special number, as A D . 1, A D . 2, etc. This system of marking 
absolutely identifies each block and, having the setting plan and 
the number on each block, the contractor should have no 
uncertainty in picking out the blocks. 

58. Another system of marking the setting plan and the 
blocks is illustrated in Fig. 14 which has some advantages in 
the way of simplicity. The different features of the building 
are lettered A, B, etc., but by this method all similar blocks 
have the same number. Thus, all the wall blocks are marked A 
and all the blocks shown marked A 5 are of the same size and 
pattern, and all marked A 4 are of the same size and pattern. 



—n—~ 

■> **• 

A- 

\ : r: A 




' • S. • ■ . .. ■ 

• .** * *. ? • > • ■ 

• *• * • \ 





Fig. 14 


38 































































































































































































































ARCHITECTURAL TERRA COTTA 


39 




Any block marked A 4 can be taken from the pile and placed in 

any position marked A 4 in the 
setting plan. In the system 
shown in Fig. 13 blocks A 4 , 
A 10 , A 16 , A 22 , etc. are all of 
the same pattern and are inter¬ 
changeable, but they must be 
(a) carefully sought and laid in the 

rotation indicated on the plan. 
Thus the mechanic must look 
after fifty or more numbers in¬ 
stead of eight or ten. 



(e) 

Fig. 15 


the block has not shrunk to 


DETAILS OF 
CONSTRUCTION 

59. The process of designing 
terra cotta, of making the vari¬ 
ous drawings required, of model¬ 
ing, and of the manufacture of 
the blocks having been described, 
some of the details of construc¬ 
tion, which are peculiar to this 
material, will next be considered. 

60. Forms of Joints. 

The joints considered in this 
article are the abutting or con¬ 
necting surfaces of the various 
blocks, and not the spaces filled 
with mortar between the blocks. 
The character of these joints is 
peculiar to terra cotta. The 
straight joint is illustrated in 
Fig. 12. These joints must be 
made so as to allow of grinding 
or chiseling off the joints when 
ie degree calculated upon or is so 


246—8 





















































40 


ARCHITECTURAL TERRA COTTA 


warped that trimming of the joints is necessary to make the 
face of the block true. As it would be difficult and expensive 
to grind the entire surface of the block, the joints are designed 
to be formed by the edges of the block, which are slightly 
raised so that any fitting that may be required may be done on 
the narrow surfaces a, b. The depressed spaces behind these 
narrow edges are filled with mortar. 

61. Another characteristic form of joint is that required 
on the top surfaces of cornices, copings, string-courses, window 

sills, or any other sur¬ 
face upon which rain 
or snow may fall. 
These joints are il¬ 
lustrated in Fig. 15 
(a), (b), (c), (</), 
and (e), which show 
five customarv forms 

J 

of such joints. 

In (a) is a rectan¬ 
gular raised joint and 
in ( b ) a segmental 
raised joint. The 
raised portions pre¬ 
vent water flowing 
into the joint. Both 
these forms are ex¬ 
tensively used, and, 
where the opening 
between the blocks is well filled with mortar, prove very 
satisfactory. 

In (c) is shown a recessed, or dovetailed, form of joint. A 
piece of sheet metal b is usually inserted to form a base on 
which the mortar may rest and to prevent the mortar passing 
through the smaller opening below. The mortar of these joints 
is finished flush with the surface of the block. 

In (d) is shown the roll joint, or covered joint. This form 
of joint afifords better protection to the mortar joint between 



18S111I11I 

P ■ $ 'v/A 


Fig.16 
















































ARCHITECTURAL TERRA COTTA 


41 


the blocks than any of the other forms described. The roll b 
is, however, often broken or injured in handling or shipping, 
or is forced off by the action of frost which necessitates repairs 
that always prove unsightly. The use of this style of joint is 
therefore not to be recommended. 

In ( e ) is shown a butt joint, such as used in stone and marble 
work and is highly recommended for use in terra-cotta con¬ 



struction. The edges of this joint are not easily marred by 
handling and the joint can be calked with mastic b, without 
necessarily breaking the edges. This style of joint is to be 
preferred to the others, as it presents no thin projecting parts 
that can be easily broken off. 















































































42 


ARCHITECTURAL TERRA COTTA 


62. Examples of Joints. —In Fig. 16 ( a ) is shown a 
terra-cotta belt-course that is built into a brick wall. The upper 
part of this course has blocks that are formed with joints of 
the raised rectangular shape. At a is shown one of these joints 
finished straight with the edge of the block, while at b the joint 
at the edge is finished with a cove. By means of this form the 


joint projecting above the block is not apparent from below. 
At a in (b) is shown a segmental raised joint. 

In Fig. 17 is shown a wall faced with terra cotta, and a pro¬ 
jecting course also formed of the same material. The blocks 
of the projecting course have a roll, or covered, joint a. These 
joints, as well as the segmental raised joints, may terminate at 
the edge of the course with a cove as previously described. 





























ARCHITECTURAL TERRA COTTA 


43 


In Fig. 18 are shown joints a of the dovetailed form. In 
this illustration it will be noted that at the front edge of the 
block, as shown at b, the joint is contracted to the same width 
as the regular vertical joint below. 

(>3. Concealed Joints.— As the sizes of the blocks used 
in terra-cotta work are necessarily small, there will be a con¬ 
siderable number of joints. It is therefore desirable to conceal 
these joints when it is possible. This can often be done with 
vertical joints, which can be concealed at panel moldings, 
pilasters, window and door trims, etc. In concealing these 
joints, one block is rabbetted 
out so as to project in front 
of another piece, thus con¬ 
cealing the joint. These 
joints are considered as con¬ 
cealed as they are not visible 
to a person looking at the 
building casually. 

In Fig. 19 is shown a con¬ 
cealed vertical joint between 
the blocks which form a 
paneled pilaster and the 
wall of a building. The 
block a is recessed on the 
back at b and the end of the 
block c is placed in this re¬ 
cess and thus made to fit closely. This method of treating 
joints is sometimes called back-jointing. 

Additional illustrations of concealed vertical joints appear 
later on in this Section in connection with the description of 
Columns and Pilasters. 



Fig. 19 


G4. Reglets. —Where a wall or a wall facing of terra 
cotta adjoins a roof construction, it is often necessary to place 
flashing and cap flashing against the terra cotta. The exact 
position of the roof should be shown on the plans and if it is 
found that the horizontal joints between the terra-cotta blocks 
will not serve to receive the upper edge of the cap flashing, 














44 


ARCHITECTURAL TERRA COTTA 


grooves, called rcglcts, should be formed in the terra-cotta 


blocks for this purpose. 


In Fig. 20 is shown a parapet wall formed of the terra-cotta 
blocks a and coped with the blocks b. At c is shown a reglet 
that has been formed in the blocks adjoining the roof, and at d, 
is shown the edge of the cap flashing e placed in this reglet. 



After the cap flashing has been set into the reglet it is usually 

secured by means of 

lead wedges / placed 

at intervals, and the 

remaining part of the 

reglet is filled with 

roofer’s cement, as at g, 

to insure a waterproof 
% 

joint. 

65. Drips. 

Terra-cotta sills, string¬ 
courses, cornices and 
copings that project be¬ 
yond the face of the 
wall below should have 
a member formed on 
the lower part, called a 
drip, that will cause the 
water to fall free from 
the wall and not run 
directly down the wall. In Fig. 20 is shown a projecting 
cornice with a drip at h, and a coping with drips at i. 


60. Securing Terra Cotta to the Structure.—Since 

terra cotta is generally a veneer, it must be fastened to and 
supported by the general structure in some way. There are 
two methods of fastening terra cotta to the supporting struc¬ 
ture : First, by bonding the blocks into the wall; and second, 
by fastening it to the structure by means of steel work in the 
form of ties, anchors, channels, angles, etc. The forms of 
steel used in this work are shown in connection with the various 
details or forms of terra-cotta work next to be considered. 













































ARCHITECTURAL TERRA COTTA 


45 


G7. Wall Facings.— In buildings of brick or stone 
masonry faced with terra cotta, the facing blocks are laid up 
like brick or stone, each course being embedded in mortar on 
the course below. Each piece is anchored with galvanized or 
painted iron wall ties embedded in the main wall or anchored 
to the steel frame to hold the terra cotta securely in place. 
Fig. 17 illustrates the application of a terra-cotta veneer to 
a brick wall, and shows the anchor i that holds one of the 
blocks in position against the wall. Most of the blocks are 
fastened to the wall in the same manner. The backs of the 
blocks are filled in solid with brickwork in cement mortar. 

G8. Wall Facings on Concrete Walls.— Fig. 18 shows 
the method of securing a terra-cotta facing to a solid concrete 
wall. In this construction the concrete wall is built first, and 
the anchor hooks, bolts, etc. are located and placed in the 
wooden forms in which the concrete is cast. In this system of 
veneering, the blocks are held in place entirely by the anchoring. 
It is therefore very necessary that the anchors be installed with 
great care. 

GO. Three systems of anchoring are shown in Fig. 18. In 
one system the hooked rod c is located so that it will come 
between the end shells of two adjoining blocks which are 
formed to fit accurately a horizontal round bar, as shown at d. 
This bar is sufficiently long to extend through the shells of both 
of the blocks and through the eye of the hooked bar. In this 
system, the hooked bars must be very carefully located so that 
they will come at these joints, otherwise they are not service¬ 
able. In the second system of anchorage, the hooked bar e is 
turned around the horizontal bar /. This latter bar is located 
back of the blocks and the blocks are anchored at the top by 
pieces of iron as shown at g. As the bar f is continuous, 
anchors may be placed at any desired location horizontally. 
The vertical location of this rod must be accurately determined 
to insure proper connections being formed. The third system 
is illustrated in the lower part of the figure. At h is shown a 
heavy wire which is left projecting from the wall surface. By 
means of this wire, the rod i is attached to the wall and fits 


46 


ARCHITECTURAL TERRA COTTA 


into the recess that has been formed in the wall for this pur¬ 
pose. The method of anchoring the blocks to the rod i is 
shown at j. 

70. When terra cotta is used as a veneer and cannot 
be filled with masonry, special precautions must be taken 
to avoid overloading the blocks and thus causing them 
to be crushed or the edges to be chipped. Where the space 
between the wall and the blocks permits of the pouring of con¬ 
crete, this space and the blocks may be filled with a cement 
grout, but this work should be done as the work progresses and 
not after the wall has been completed to a story height. 

Terra-cotta facings of the character mentioned are sometimes 
supported at intervals by means of angles such as shown at k, 
Fig. 18, called shelf angles. These are secured to the concrete 
structure by means of bolts which are placed in the concrete 
forms at the required locations before the concrete is poured, 
and after the forms have been removed the angles are attached 
to the wall by means of these bolts. 

These angles must be accurately located and the lower flange 
should line with the horizontal joint in the terra cotta so that 
one course of blocks may have a direct bearing on the angle. 
The blocks resting on the angle should also be anchored to the 
angle, which is set away from the face of the building by means 
of washers. This permits of running wire behind the angle 
and securing the terra-cotta blocks in place, or of the use of 
bent rods such as shown in Fig. 18. 

71. String-Courses.— String-courses are usually built 
into the wall as shown in Fig. 16. This example consists of 
two courses of terra cotta. The lower member c extends into 
the wall as far as the width of one brick and, since it has to 
support the weight of the construction above, it is filled in solid 
with brick and mortar. The upper course, showm at d, has a 
greater projection and also extends into the wall. Both these 
courses are filled with brickwork as far as the line of the wall 
face. The projecting part of the upper block is not so filled. 
Metal anchors of the form shown at e are used to tie the pro- 


ARCHITECTURAL TERRA COTTA 


47 


jecting blocks to the wall. The blocks have holes formed in 
the upper shell, as shown at f, to receive the anchors. 

72. Cornices, Medium Size.— A medium-sized cornice 
is shown in Fig. 17. The wall supporting this cornice is faced 
with plain terra-cotta blocks b, equal in thickness to one thick¬ 
ness of brick. The cornice consists of two rows of blocks. 
The lower blocks are richly molded and have a considerable 
projection in front of the face of the wall. This course must 
provide a certain amount of support to the upper course and 
therefore must be filled with masonry and anchored to the 
backing by anchors such as shown at h. The blocks of the 
upper course d extend back into the wall so that they may 
have good bearings, or supports, and may be covered by the 
masonry above. This masonry resting upon the backs of the 
blocks prevents them from tipping outward. These blocks also 
support a considerable load of masonry, consequently must be 
filled with brickwork as far as the face of the wall. The pro¬ 
jecting portion of this cornice is not filled with masonry, as it is 
desirable that this part be as light as possible so that it will 
have no tendency to drop or tip. The blocks in this course 
should be carefully anchored to the brick wall as shown at e. 
The course / projects in front of the face of the wall. Above 
this course the wall is faced with the blocks g. 

73. Large Cornices. —Large projecting cornices of 
terra cotta usually require to be supported by the structural- 
steel frame or by the solid masonry walls of the building. 
Cornices that are designed for buildings having a steel frame 
usually have an interior framework of steel shapes, and this 
frame is connected with the frame of the building in such a 
manner that the entire cornice is supported by the steel work 
of the building. This form of construction is very complicated 
and the structural engineer who designs the frame of the 
building usually designs it so as to support the cornice properly. 
The terra-cotta manufacturer will then design the secondary 
steel members that are required for his work. 

74. Cornices for solid masonry walls, such as those 
illustrated in Fig. 21, are usually so designed that the lower 


48 


ARCHITECTURAL TERRA COTTA 


members of the cornice will project somewhat to form a 
bracket or corbel on which the succeeding members, which have 
a greater projection, may rest. These lower members are filled 
with masonry and also anchored to the walls in the usual man¬ 
ner. The upper courses are provided with structural-steel 
forms li which are also anchored and secured to the wall. In 
this form of construction it is customary to extend the wall of 



islli 


mmm 




Iflll 




■Ml 

Mggfi 




HHH 












Mis® 




Fig. 21 


the building to a sufficient height above the cornice to form a 
mass of material that will more than balance the weight of the 
projecting portions of the cornice. 

75. The blocks that form this cornice are indicated at 
a, b, c, d, and e in (a). The outline of an additional block is 
indicated by the dotted line at /. This block cannot be shown 
in the view given, but occurs above the blocks b and fills the 
space between the brackets c. 






































































ARCHITECTURAL TERRA COTTA 


49 


The blocks a and b are filled with masonry and are also 
anchored by means of the tie-rods g. These blocks project 
beyond the wall surface and help to carry the brackets c and 
the wall blocks indicated at / between the brackets. The pro¬ 
jection of the brackets c is so great, however, that the anchors 
and back filling are not sufficient to hold them in place. Steel 
angles h are therefore installed above each bracket to form a 
cantilever support. The angles are separated slightly to allow 
the rods to be placed between them for anchoring into the wall 
and for the suspension of the blocks. Wall anchors, one of 
which is shown at i, are provided to hold these angles in place 
and are usually several feet in length. Each anchor has a plate 
at the lower end, as shown at j, to anchor the rod to the wall. 
The upper ends of the anchors are fastened to the continuous 
channel k which runs parallel with the wall. By means of these 
anchors and fastenings, the steel angles are prevented from 
being pulled out of the wall by the weight of the cornice. 

The bracket blocks c are supported and kept in place by a 
length of iron pipe m which is placed inside the bracket. One 
end rests on the brick wall and the other end is suspended from 
the channels by means of a rod /. This rod has a thread and 
nut on the upper portion. By turning the nut the bar m is 
raised until it comes in contact with the upper shell of the 
bracket and holds the bracket firmly in place. The blocks d are 
formed to fit over the angles li and rest on the brackets and 
the wall blocks between the brackets. The top members of the 
terra-cotta cornice, shown at e, rest on the blocks d and are 
anchored to the wall by rods, one of which is shown at n. 

In (&) is shown a perspective of the steel work used in this 
system of supports with the various members assembled. The 
series of cantilever angles are shown at a, the continuous chan¬ 
nel at b, and the anchorage and suspension rods as just 
described. 

76. Lintels. —In Fig. 22 is shown an entrance to a build¬ 
ing which has walls faced with terra cotta. The jambs and 
lintel of the opening are also formed of the same material. Since 
the terra cotta is only a veneer for the brickwork, it is necessary 


ILT 497—9 


50 


ARCHITECTURAL TERRA COTTA 


that steel supports be provided to carry the terra cotta as well 
as the brickwork over the opening. 

Eig. 23 (a) represents a section taken through the center of 
the lintel over the entrance shown in Eig. 22. The steel sup¬ 



ports that carry the masonry and terra cotta consist of three 
angles, as shown at a, b . and c, and one channel d. The 
angles a and b carry part of the brick wall, and the angle c and 
channel d carry the remaining part of the wall and the terra¬ 
cotta lintel. The steel member d supports the terra-cotta lintel 

































































































ARCHITECTURAL TERRA COTTA 


5.1 


course c, which is suspended from the steel by means of rods f 
and anchored by the anchors g so that it is perfectly strong 
and rigid. 



In this figure, sections are shown through the blocks which 
form the courses e, h, and i to illustrate how the blocks are 
formed to fit around 
the steel work and to 
show the rods and 
anchors that secure 
them in place. In (b) 
is shown a view of the 
steel supports a, b, c, 
and d that hold up the 
lintel. At e is shown 
one of the rods that 
carry the lower course 
of terra cotta. These 
rods are placed be¬ 
tween the blocks of 
the lower course of 
the lintel, the upper 
ends of the rods are 
secured to the steel 
channel by means of 
clips f, and the lower 
end is bent around 
the short bar g, which 
extends through the 
end shells of two ad¬ 
joining blocks. At h 
is shown a rod which 
is formed around the 

Fig. 23 

bar g and also over 

the horizontal flange of the angle a. This rod prevents the 
block from tilting when the succeeding course of terra cotta is 
put in place on top of it. At i and j are shown the galvanized 
iron bars that are used to anchor the terra-cotta blocks h and i 
in (a) to the steel lintels. 
















































































































52 


ARCHITECTURAL TERRA COTTA 


The terra-cotta blocks j, k, and l in (a) are bonded with the 
brick wall and also anchored by bars as in the regular form of 
construction. 

The terra-cotta lintels of the entrances shown in 
Figs. 2, 3, and 5 are all formed of courses of blocks and 
carried by steel members that are concealed in the masonry, 
thus permitting the exposed under side of the lintel, called the 
soffit, to be finished to correspond with the jambs, as is shown 
in Fig. 5. The principle involved in the construction of these 
lintels is the same as that shown in Fig. 23, the form of the 

blocks and the steel work being 
adapted to meet the requirements 
of the different designs. 

77. Window Mullions. 

Window mullions or slender piers 
that are formed of terra cotta or 
have a facing of that material, 
should be provided with steel posts 
formed of Ts, angles, or gas pipe, 
to which the terra cotta may be 
anchored, and which will give 
stiffness to the piers. 

In Fig. 24 is shown a mullion 
that has a terra-cotta facing. A 
steel T bar a is used to reinforce 
the mullion. A short iron bar b is placed in an opening in the 
top of the terra-cotta block and this is anchored to the T bar by 
means of a heavy wire. The bar b extends into the bottom shell 
of the succeeding block. Round or square bars of iron 
are sometimes used as anchors, one end being formed to turn 
down into the opening in the top of the block and the other end 
being formed to fit around the T. This method, however, does 
not anchor the bottom end of the succeeding block. 

In this illustration it will be noted that the lower part d of 
the mullion is formed on the terra-cotta sill-course. This is 
done to secure a level bearing for the block e, as the sill is 
formed with a slope, as shown at /. 




























ARCHITECTURAL TERRA COTTA 


53 


■ r". 

'A—” " 








• - '• * • 
































- jVAl 1 1.-IV.V.-^V.'R r.'.UII ■ \y 



Examples of mullions which have steel reinforcement are 

shown between the 

=t- windows over the 

front entrance of the 
bank building illus¬ 
trated in Fig. 3, be¬ 
tween all windows of 
the residence shown 
in Fig. 7, and between 
the windows of the 
apartment building 
shown in Fig. 8. This 
reinforcement is ab¬ 
solutely necessary for 
the mullions shown in 
Fig. 7, as the mullion 
is too small to permit 
of sufficient masonry 
to give any 
to the terra 
cotta or to permit of 
anchoring the various 
mullions. The transom 
blocks which form the 
bars shown in this il¬ 
lustration are also re¬ 
inforced with steel. 

78. Pilasters. 

In designing pilasters, 
the forms of the 
blocks and manner of 



backing 

strength 




(a) 



'psmmwMm jointing them where 
they intersect with 
wall blocks require 
particular considera¬ 
tion in order that the 
vertical joints may be concealed or, at least, not easily seen. 











































































































































54 


ARCHITECTURAL TERRA COTTA 


The pilaster shown in Fig. 25 has a paneled face and each 
course in the width of the pilaster is formed of three pieces. 
T he panel is formed of one piece and the side members of the 
other pieces. At a in (b) is shown a plan of one side piece, 
and at b a portion of the panel. At c and d the manner in 
which the block is formed to conceal the vertical joints is 
shown. 1'he moldings at the top and bottom of the panel, as 



Fig. 26 


shown at a, a in (a), are formed on the same blocks as the 
top and bottom sections of the panel. 

The pilaster shown in Fig. 26 has horizontal joints known 
as rusticated joints. This is a very practical design for large 
blocks, as a slight warping of the blocks in the burning is less 
apparent than in the plain smooth-faced pilasters. In the 
rusticated design, the horizontal joints between the blocks are 
not conspicuous, as they are located at the tops of the recessed 
























































































































ARCHITECTURAL TERRA COTTA 


55 


surfaces between the projecting parts of the blocks. This 
design requires a somewhat different form of joint, however, 
at the intersection of the pilaster with the wall, as one part of 
the block projects beyond the other portions. In (b), at a, are 
shown these projecting parts, and at b is shown the return 
which is formed on the wall block c. In (c) is a view of this 
joint, showing the projecting part of the wall block c extending 
behind the similar portion of the pilaster block. The por¬ 
tions d and c of the joint will appear as shown. These joints 
should be made as thin as possible so that they will not be 
easily seen. This form of block allows of a square joint between 
the two intersecting blocks instead of a miter joint, and any 
cutting of the blocks that is necessary to make them fit properly 
may be easily done without disfiguring the joint. 

79. Columns. —Columns of terra cotta are built up in 
sections from 10 to 16 inches in height, called drums, from 
their cylindrical drum-like shape. For columns not exceeding 
14 inches in diameter these drums can be made in single pieces. 

In the case of columns of large diameter, it is not practical 
to make the drums in one piece, as slight inequalities of shrink¬ 
age are likely to occur. The best practice is to use a sufficient 
number of vertical joints to make the drum of four or more 
pieces, depending upon the diameter of the column. The ver¬ 
tical joints should be continuous for the whole length of the 
shaft wherever practicable. The heights of the courses should 
not exceed 16 inches. 

If the terra-cotta column is to enclose a structural-steel 
column, the drums must be made in pieces so that they can be 
placed around the steel column. 

80. In Fig. 27 (a) is shown a terra-cotta column of small 
size, in which the drums can be made in one piece if desired. 
The drums are shown at a, b, c, etc. The drum b is in one 
piece, and a and c are each in five sections. A plan of the 
drum b is shown in (c) and a plan of the drums a and c in 
(b). The plan ( b ) shows the outer shell upon which the 
flutes are cast, also the radiating webs and the vertical joints 
between the sections. The right-hand side of the plan shows 


246—9 


56 


ARCHITECTURAL TERRA COTTA 


the top of the block with anchors d holding the blocks together, 
also the raised parts of the bed joints e, which are ground 



when necessary to make the blocks fit together. At / in (a) is 
a vertical section through a block, showing the horizontal ribs 

























































































' s =d== ^ 


d 


C\ /~~\ AAnn 

d 

_ 



c / 





a 



(a) 


Fig. 23 



57 






































































































































































































































































58 


ARCHITECTURAL TERRA COTTA 


and the raised joints that are shown in plan at e in ( b ). The 
left-hand side of the plan (b) shows the radiating webs g and 
the joints h. The capital is generally made in sections. A 
plan of the capital of the column, in which the observer is look¬ 
ing upwards, is shown in ( d ). The ornamental portion of the 
capital is divided into five parts and the square abacus i into 
four parts. 

81. When the column is built, the center of the column as 
well as the hollow spaces in the block are filled with masonry. 
Concrete is the cheapest and best material to use for this pur¬ 
pose. A column such as the one just described is not strong 
and should not be expected to support a great load. When 
there is a considerable load to be supported a steel column 
should be placed inside the terra cotta one in the manner that 
will be described later in connection with Fig. 29. 

82. A design of column known as a banded column is 
shown in Fig. 28 (a). With the exception of the base af and 
the capital b, the sections that form this column are all of the 
drum shape, made without vertical joints. The advantage of this 
design, for terra-cotta construction, is that the plain sections c, 
being located between the fluted sections d, conceal irregularities 
in the flutes that may be caused by the burning and which would 
be apparent were these fluted sections placed together. The 
forms of the shell and the interior webs of this column are 
similar to those of the column shown in Fig. 27. 

A plan of the base block a in (a) is shown in (c). A plan of 
the cap viewed from the under side is shown in ( b ). Both 
base and cap are formed of four pieces which are clamped 
together as shown at c in both these figures. The clamps are 
shown in dotted lines, as they occur on the upper side of the 
capital and could not be seen in the view given. A plan of the 
circular portion / of the base is shown in (c), and the plan ( d) 
represents the fluted drums d in (a). 

83. Columns that are required to support a weight in 
excess of the load the terra cotta will safely carry should be 
provided with a structural-steel column in the center. If the 
terra-cotta column is small and the sections are in single drums. 





P/an of Base on Line of A~D. 


Lb) 


Fig. 29 


59 





















































































































































































































































60 


ARCHITECTURAL TERRA COTTA 


it will be necessary to erect the steel column first and lower the 
terra-cotta drums down from the top over the steel column. 

Columns of large dimension cannot be economically or suc¬ 
cessfully formed in single drums, but must be built up of 
segments. Columns of this character usually contain structural- 
steel supports, and the terra-cotta segments must be designed to 
fit around the steel work which has been previously erected. 

To conceal the vertical joints as much as possible in the com¬ 
pleted column, frequently flutes and beads are employed in the 
design and the vertical joints are located in these members. 
Segments that form the columns should be anchored together 
by means of iron clamps hooked down into holes cast in the 
shell or webs of the units and the hollow spaces in the blocks 
should be filled with brickwork or concrete. 

% 

84. In Fig. 29 (a) is shown a fluted column having a 
molded base and an ornamental capital. This terra-cotta 
column encloses a steel structural column and is of a large 
diameter. The base, shaft, and cap are formed of several 
units and the joints between them are indicated in the illus¬ 
tration by heavy lines. 

In ( a ) is shown the complete column. The base block a is 
formed of four parts, as in the square part of the base shown in 
Fig. 28. The molded base b, Fig. 29 (a), is shown in plan 
in ( b ) and is formed of eight segments which are bonded 
together by means of iron clamps c. A section through the 
fluted shaft of the column, taken on the line CD in (a), is 
shown in (c), six segments being used to form the drum. 
These are also anchored together by means of clamps c. 

The right-hand part of this section is taken through the joint 
and therefore the clamps c can he seen. The left-hand side of 
the section is taken through the middle of the block and shows 
the concrete or cement filling at d. A plan of the under side 
of the cap, taken at E F, the observer looking up, is shown 
in (d) ; the heavy lines indicate the jointing of the four parts 
that form the cap. Joints on one side of the cap are shown 
at e in (a) and those of the other side of the cap are shown 
at £ in (c). 


ARCHITECTURAL TERRA COTTA 


61 


The steel column around which the terra-cotta column is 
formed is shown at / in (b), and the space that is filled with 
concrete or brickwork is shown at d. 

An example of cylindrical columns formed of plain blocks 
of teua cotta is shown in Fig. 3. In big. 2 are shown columns 
that ha\ e structural-steel members in the cores. These columns 
aie designed so that the vertical joints between the blocks occur 



ornamental beaded treatment. 

85. Cartouches.— A cartouche is a form of ornamem 
consisting generally of a panel in the shape of a shield, oval, or 
rectangle, which is surrounded by ornaments consisting of rib¬ 
bons, scrolls, foliage, etc. The central panel may be decorated 
with a coat of arms, a motto or some similar motif, or left 
plain. Cartouches are used frequently as a means of decora¬ 
tion and their ornamental character makes them expensive to 
execute in stone. They are, however, comparatively inexpen- 



















































(32 ARCHITECTURAL TERRA COTTA 

sive when made of terra cotta. A small cartouche is shown in 
Fig. 30. An elevation is shown in (a) and a side view in ( b ). 
The method of securing the cartouche to the wall is shown in 
( b ), in which the block, of which the cartouche is a part, 
extends back into the wall as shown at a, and an anchor b 
firmly secures the cartouche to the wall. 

86. Cartouches are often quite large and made up of sev¬ 
eral blocks. The joints in such cases are carefully designed so 


Fig. 31 

as not to cross the principal parts of the cartouche. An 
example of a large cartouche is shown in Fig. 31. Joints are 
shown on each side of the helmet and in corresponding posi¬ 
tions in the lower part of the cartouche. The shield containing 
the eagle is in one piece, as a joint through this part of the 
cartouche would be unsightlv. 

O w/ 



63 


ARCHITECTURAL TERRA COTTA 

87. A very conspicuous example of the use of terra-cotta 
cartouches in the design of the building is shown in Fig. 8. In 
this design cartouches form the central parts of ornamented 
panels, as in the panel immediately over the entrance to the 
building; in other places they are used as inserts in the wall. 

88. Balustrades.— Vertical members of terra cotta, such 
as balusters, urns, finials, etc., are usually formed of small 
pieces and held together by round iron rods extending up 



through hollow cores in the centers. On each end of these rods 
is a nut and washer, and when the top nuts are tightened the 
different pieces of terra cotta that compose the baluster or 
finial are drawn closely together. 

When balusters are short, each can be cast in a single piece 
having a hollow core to receive the rod and to permit of proper 
shrinkage in the burning. Long balusters can be molded in 
halves, which, after drying, are placed together and the joints 
smoothed off and finished so they will not show. The com- 


! 


246—10 








































































































































































































ARCHITECTURAL TERRA COTTA 


64 

pleted baluster is then placed in the kiln and burned. When a 
long baluster consists of a base, shaft, and cap, however, joints 
are formed in the baluster so that it may be cast in three 
pieces, each of which is small. The twisting and warping due 
to burning is thus reduced to a minimum. 

Balustrades are formed of a series of balusters which rest 
on a terra-cotta base and are covered at the top by a terra¬ 
cotta cap, or railing, and the balusters are anchored to this base 
and cap to make a strong and rigid construction. 

80. A portion of a balustrade of this description is shown 
in Fig. 32 ( a ) and a section through the balustrade and one 
of the balusters is shown in ( b ). In (a) an elevation of the 
base on which the baluster rests is shown at a, the baluster at b, 
and the cap, or railing, at c. The balustrade terminates at the 
end of the building in a pier as shown at d. This pier is faced 
with regular-shaped terra-cotta blocks and is constructed in the 
same manner as terra-cotta faced walls. At c is a plain pilaster 
adjoining the pier. 

The dotted lines at / indicate a rod that extends from the 
base, through the baluster, and into the cap. In this illustration 
the rods are inserted in everv other baluster instead of in each 

J 

one. In (b) is shown a section through the balustrade in 
which the baluster is shown to be formed of two parts, b and c. 
Dowels are formed on the base a and also on the members of 
the baluster which fit into corresponding recessed parts as are 
shown at d, e, and /. At g is shown a flat bar that extends the 
entire length of the balustrade and through which the rods pass 
and are secured. This portion of the balustrade requires to be 
completed before the cap members are set in place. 

90. Domes.—Architectural terra cotta has come into wide 
use as a facing material for the interior and exterior surfaces 
of domes. It is particularly adapted to this use because the 
material is light in weight and permits of extensive color 
effects, and is impervious to the weather. 

The terra-cotta facing is supported on a frame made of 
rolled-steel sections of light weight, or, more generally, on a 
light concrete dome which may or may not be supported on 



L T 497—10 




























































































































































66 


ARCHITECTURAL TERRA COTTA 


steel shapes. Fig. 33 shows the construction of a dome made 
of concrete which is faced both on the outside and on the inside 
with terra-cotta blocks. In (a) is a cross-section through one 
half of the dome and in ( b ) is a plan of part of the outside 
terra cotta. The reinforced concrete which forms the struc¬ 
tural base on which the terra cotta rests is shown at a in (a). 
The steel angles to which the outside terra-cotta work is 
attached are shown at b; the exterior terra-cotta blocks c 
rest on the angles as well as on the concrete and are also wired 
to the angles. 

The blocks used on the outside of the dome have lips that 
project over the next row of blocks below. The vertical joints 
between these blocks are rectangular raised joints, as shown 
in (c) and (/). A dome constructed in this* manner should 
have a waterproof coating of felt and tar above the concrete 
and under the terra cotta to prevent water from working its 
way through the dome from any leaks that may occur in the 
raised joints of the outside terra-cotta covering. This water¬ 
proofing is indicated at / in views (a), (c), and ( d ). All the 
outside joints should be filled with roofer’s elastic cement to 
insure their permanence and waterproofing value. 

A section through the individual blocks is shown at c in (c). 
The steel angles b support the blocks which rest against them, 
and, in addition, the blocks are wired to the angles as shown 
at g,g f . These wires extend between the joints of the blocks 
and are secured to pins that pass into holes in the adjacent 
blocks. A section through the raised joints is shown in (e). 
The wire just referred to is placed in the joints between the 
blocks. The joint is rabbetted, which tends to make it water¬ 
proof, but should nevertheless be filled with good elastic 
cement. The tiles themselves are also set in elastic cement. 

The inside lining of the dome, as shown in Fig. 3o (a), is 
formed of blocks e secured to the concrete dome by means of 
stout wires d that are set in the concrete when it is cast. These 
wires, shown more clearly in (c) and ( d ), extend below the 
lower surface of the concrete and their lower ends are fastened 
to short rods that extend through holes that occur in all the 
blocks and thus the blocks are held securely in place. 


ARCHITECTURAL TERRA COTTA 


G7 


SHIPPING AND HANDLING TERRA COTTA 

91. Packing'. —Terra cotta is usually shipped from the 
factory in box cars, as they afford better protection for the 
blocks than open cars do. 

The blocks should be carefully packed with plenty of hay or 
straw surrounding them. They should be laid in courses in the 
car and be so placed that no finished edges or faces come in 
contact with the car or adjoining pieces. All blocks should 
be so braced or wedged with the straw or hay that they cannot 
move about in the car. 

The courses, or layers, in the car should consist of blocks 
having consecutive numbers, so that when the blocks are 
removed from the car upon its arrival at its destination they 
may be stacked in corresponding layers, or courses. This 
method will facilitate finding the blocks in their proper order 
when they are to be placed in the wall. 

92. Receiving and Checking. —When shipping the 
terra cotta, the manufacturer always sends to the contractor 
who is to erect the material a list of the pieces included in the 
shipment. 

When the blocks are received at the building they should be 
checked with the list, and if any listed pieces are missing, the 
factory should be notified immediately so that the pieces needed 
may be shipped without delay. 

93. Assorting and Stacking the Blocks. —As there 
is danger of the terra cotta being chipped by frequent and 
careless handling, it should be assorted as it is received at the 
building and stacked in such a manner that it will not need 
further handling until it is required to be placed in the walls of 
the building. For this reason it is customary to form separate 
stacks of the blocks that form each part of the design, and to 
place the blocks that are required first at the top of the stack. 

In stacking the blocks, care should be taken to prevent all 
edges and finished faces from coming in contact with hard sub¬ 
stances or with one another. The best method is to pile the 
pieces in layers with strips of boards between the layers. 


68 


ARCHITECTURAL TERRA COTTA 


If blocks are not to be used immediately, they should be stored 
in a shed or be covered with boards and waterproof paper to 
prevent their being injured. If a block is broken it will take 
from six to eight weeks to send to the factory and duplicate it. 

04. Handling’ the Blocks. —In conveying the blocks 
from the stacks to the scaffold, the pieces should be carried 
singly, if possible, one block of ordinary size being a good load 
for one man. If it is necessary to use a wheelbarrow, the block 
should be placed on straw with the face up and only one block 
should be carried at a time, unless the blocks are very small. 
In that case several small blocks may be placed in the wheel¬ 
barrow, provided that straw is carefully packed around them. 


SETTING THE TERRA COTTA 

95. Backing-Up the Blocks. —Terra cotta is backed up 
with masonry in much the same manner as cut stone or face- 
brick work. When terra cotta is used as a veneer for a masonry 
wall, the hollow spaces in the blocks are generally filled 
with masonry. When the terra cotta projects beyond the face 
of the wall, the masonry filling of the blocks usually does not 
extend very much beyond the face of the wall, consequently 
steel anchors, such as have already been described, are used to 
tie the terra cotta to the masonry. These anchors if not 
embedded in masonry should in all cases be covered with 
cement grout as a protection against rust. It is dangerous to 
omit this protection. 

Terra-cotta facings for concrete walls frequently do not 
permit of filling the back of the blocks with masonry, but grout 
may be poured back of the blocks to fill the voids, if the 
circumstances require it. 

9(>. Fitting. —While terra-cotta blocks are usually fitted 
together and the edges jointed at the factory, occasions arise 
when it is necessary to cut the blocks at the building before they 
can be set in place. This may be due to errors in measure¬ 
ments or to irregularities in the structural parts of the building. 



ARCHITECTURAL TERRA COTTA 


69 


The shells and webs of the blocks sometimes require to be cut to 
fit structural-steel members or to provide additional openings 
into which anchors may be placed. This cutting should be done 
only by skilled workmen and every precaution should be taken 
not to injure the block either on the exposed face or in the 
parts that are essential to its strength and anchorage. It is, 
however, not often necessary to fit the terra cotta at the 
building. 

97. Anchoring-. —The method of anchoring terra-cotta 
blocks will depend upon the. form of the blocks and the struc¬ 
ture to which they are to be attached and must be adapted to 
meet the peculiar requirements of each case. 

The most essential feature of the anchor, next to its strength, 
is that it shall form a rigid connection between the block and 
the backing to which it is fastened. The manner in which it is 
made rigid will depend upon whether the anchor is of a form 
that can be adjusted or one that is of a fixed form. 

Horizontal anchors that connect with the blocks and extend 
back into the masonry do not require to be adjustable. They 
are set into the holes of the blocks and masonry is built around 
the opposite ends so that when the mortar becomes hard the 
anchors cannot be moved. 

Anchors that fit over a structural-steel member back of the 
block are sometimes formed by bending one end to fit into the 
block. The anchor is then placed in position and by means of a 
hammer, the opposite end is bent so that it will accurately fit 
over the steel. This method is possible only where the anchors 
are formed of small bars or straps that can be bent without 
endangering the terra-cotta blocks. 

When heavy anchors are used to fit over structural-steel 
members, they may be formed with turned-down ends and of 
such lengths that they can be easily driven into position. They 
may be made slightly longer than required, and when set in 
place may be wedged at either end by means of small pieces 
of broken terra-cotta blocks until they are rigid, after which 
mortar should be slushed around the anchor connection at the 
block to make sure that the anchor will remain in place. 


70 


ARCHITECTURAL TERRA COTTA 


For overhanging blocks that are carried by suspension rods, 
an adjustable form of hanger is used. The lower end of the 
rod is formed with a hook through which a bar extends hori¬ 
zontally into adjacent blocks. The upper end of the suspension 
rod is provided with a screw thread and nut. The horizontal 
bars afford a bearing for the terra cotta and the sus¬ 
pension rods are brought to a rigid condition by screwing down 
the nuts on the upper ends. In this manner the entire weight 
of the block is carried by the rod. 

08. Bedding’ in Mortar.— All terra-cotta blocks should 
be well bedded in mortar and pressed down so that each piece 
will*have a uniform bearing throughout the length of the block. 
Mortar joints for the top surfaces of all sills, projecting 
courses, cornices, and copings should be carefully formed so 
that no openings will be left through which water may enter 
the joints. 

In setting heavy pieces of terra cotta, wooden wedges of 
uniform thickness are sometimes placed in the mortar bed to 
secure joints of uniform sizes, as the weight of the block would 
otherwise cause the mortar to be pushed out of the joint before 
the mortar becomes hard. 

The mortar joints at the face of the wall frequently are fin¬ 
ished as the blocks are laid, instead of being pointed later. 
When this is to be done, a rough mortar joint is formed with 
the trowel when the block is put in place and in the course of 
several hours, when the mortar has become sufficiently hard, 
it is smoothed with a tool to secure the form of joint desired. 

01). Filling.—For large projecting cornices, such as 
shown in Fig. 21, concrete is sometimes used as a filler, as 
shown at o, instead of terra cotta. 

On this filler is placed a row of regular building tiles p to 
form a surface on which the sheet-metal covering q may be 
laid. This covering extends over the front member of the 
cornice and returns into a groove, or reglet, that has been 
formed in the face of the blocks, as shown at r. It is secured 
in place by means of wedges of lead and the intermediate 
spaces are filled with roofer’s elastic cement. At the wall, the 


ARCHITECTURAL TERRA COTTA 


71 


sheet metal turns up as shown at s, and is cap-flashed in the 
usual manner, a c shown at t. 

100. Mortar.— Mortar for setting of terra cotta is usually 
formed of cement and sand, with a small amount of thoroughly 
slaked lime added to make the mortar more plastic and thus 
facilitate its spreading. Mortar for this purpose should be 
composed of one part Portland cement and two parts of clean 
sand and part of hydrated lime. 

Lime mortar is not suitable for this form of construction, as 
it sets slowly and therefore prevents rapid progress with the 
work, for the weight of the terra cotta would squeeze the 
mortar out of the joints before it had time to become hard. 
Lime mortar will, moreover, disintegrate in time and leave 
open joints. 

When the joints in the terra cotta are to be pointed after the 
work has been completed, the mortar in the joints should be 
raked out to a depth of from J inch to 1 inch as soon as the 
blocks have been set. Also, loose particles of mortar on the 
face of the blocks should be removed to facilitate cleaning 
the blocks later on. 

101. Protecting the Terra Cotta. —All projecting 
members of terra-cotta courses should be temporarily pro¬ 
tected after the blocks are laid, so that they will not be broken 
by falling bricks or other building material. Planks or boards 
are used for this purpose and it is usually specified in the car¬ 
penter’s, mason’s, or the terra-cotta contract, that the contrac¬ 
tor shall protect all terra-cotta work until completion of the 
building. A board slightly wider than the projection should be 
laid along all projecting members and fastened securely in 
place by crosspieces tacked to window frames, floor joists, or 
wherever it is possible to make a fastening. Ornamental panels 
or other ornamental terra-cotta work should be entirely covered 
to make sure that they will not be injured during the process 
of building. 

102. Terra-Cotta Foreman.— For a large or compli¬ 
cated job of terra cotta, a terra-cotta foreman, who is an expert 


ARCHITECTURAL TERRA COTTA 


in this work, is sometimes employed, at the owner’s expense, 
to supervise the terra-cotta work. 

It is the duty of this foreman to see that the material arrives 
on the building site at the proper time and in sufficient quan¬ 
tities so that there will be no delay in erecting the building. He 
also checks off the blocks to see that they are all at hand and 
causes them to be piled in such order that they can be taken as 
wanted without unnecessary delay or lost’labor. 

He is responsible for the proper stacking of the blocks to 
keep them from injury and for seeing that they are covered up 
and protected with planks or boards. The supervision of the 
actual setting of the blocks is also part of the duties of the 
terra-cotta foreman. 

103. Washing and Pointing the Terra Cotta. —As 
a general rule, terra-cotta blocks are laid up without the joints 
being pointed, the rough mortar of the joint being raked out 
slightly before it becomes hard. Just before the completion of 
the building, the face of the terra-cotta work is washed and 
the joints pointed. This work can be done by the masons who 
set the terra cotta or by another contractor who is a specialist 
in this line of work. The latter is the usual practice for clean¬ 
ing buildings composed of brick or stone walls and terra-cotta 
trimmings, and one contractor is then responsible for the clean¬ 
ing and pointing of the face of the entire building. 

Lmglazed terra cotta should be washed with a weak solution 
of muriatic acid such as is used in cleaning brickwork, a 
3-per-cent, solution being sufficiently strong for this work. This 
may be applied with a coarse brush and the surface of the terra 
cotta scrubbed until all cement stains and lumps have been 
removed. Steel brushes, such as are used in cleaning stone and 
brickwork are not suited for cleaning terra cotta, however, as 
the steel bristles may injure the glaze of the material. Steel or 
iron tools, pails, etc., should never be used in connection with 
acid in cleaning the fronts of buildings. Glazed terra cotta 
never requires acid. The best cleaning material to use is an 
abrasive soap or washing powder. Lumps of mortar should be 
soaked with water and removed with a wooden stick. 



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73 Fig. 34 





























Fig. 35 


74 























75 


Fig. 36 























































Fig. 37 


76 
















































































78 


ARCHITECTURAL TERRA COTTA 


The pointing materials may be ordinary cement-and-sand 
mortar, white-cement mortar, or colored cement mortar, as 
may be desired. For white enameled terra cotta, white mor¬ 
tar is generally used to make the joints as near the color of the 
terra cotta as possible. Pointing mortar may be colored any 
desired shade to match any color of terra cotta, but mineral 
colors only should be used, as coloring matter composed of 
vegetable colors will fade. 

Joints in terra cotta are usually close, and the pointing is 
done with a tool about an eighth of an inch in thickness. This 
tool makes a joint that is slightly depressed at the center and 
the mortar is pushed firmly against the edges of the blocks. 


EXAMPLES OF TERRA-COTTA WORK 

104. One of the most noteworthy examples of terra cotta 
applied to the exterior of a building is shown in Fig. 34, which 
is a view of the Woolworth building in New York City. The 
general color of this building is a light cream, while the panels 
between the windows are finished in various colors such as 
golden yellow, green, sienna, and blue. The style of architec¬ 
ture employed is Gothic. The terra cotta, which is mat-glaze 
finish, was set in mortar composed of cement, white sand, and 
a waterproofing compound. The building was washed down 
with Gold Dust washing powder and sand grit, no acid being 
used in cleaning. 

105. Notwithstanding the lightness and delicacy that char¬ 
acterize the appearance of this building, the details when seen 
at close range are very large in actual size, as shown in Fig. 35. 
In this illustration is shown the figure of a man which gives an 
idea of the relative size of the ornament. Other examples of 
the details used in this building are shown in Figs. 36 and 37. 
In Fig. 38 is shown a detail of two windows in one of the 
upper stories of the building. At the sills of the lower windows 
is shown the method of protecting portions of the ornamental 
work by means of boarding. 





























